JP7497011B2 - Method for producing carbosilane - Google Patents

Description

The present invention relates to an efficient method for producing carbosilanes.

Carbosilanes having an Si--C bond are important compounds that are used as precision synthesis reagents, intermediates, etc. for producing various functional chemicals or various functional materials, such as medicines, agricultural chemicals, optical materials, and electronic materials.
A well-known general method for producing these carbosilanes is to react a chlorosilane, an alkoxysilane, or the like with an organometallic compound such as a Grignard reagent or an organolithium reagent (Method A) (Patent Document 1, Non-Patent Document 1).
Meanwhile, a method (Method _B ) has been reported in which a catalytic reaction promoter is used to decarboxylate (decarboxylate refers to the elimination reaction of CO2) an acyloxysilane having a specific Si-OCOR' bond (OCO is an oxycarbonyl group, O-C( ₌ O); R' is a trichloromethyl group (CCl3), a pentafluorophenyl group ( _C6F5 ), or a trifluoromethyl group ( _CF3 )) to produce a _carbosilane having a Si-R' bond (Method B) (Non-Patent Documents 2 and 3, Patent Documents 2 and 3).
In method (B), different reaction accelerators are known depending on the type of acyloxysilane. For example, when the acyloxysilane is Me ₃ Si—OCOCl ₃ (Me is a methyl group), triethylamine or N-methylpyrrolidine is used (Non-Patent Document 1), and when the acyloxysilane is R″Me ₂ Si—OCOCl ₃ (R″ is a methyl group, a chloromethyl group, a phenyl group, a trimethylsilyl group, or a hydrogen atom), quaternary ammonium salts (Et ₃ (PhCH ₂ )NCl, Bu ₄ NBr; Et, Ph, and Bu are an ethyl group, a phenyl group, and a butyl group, respectively) or a potassium salt/crown ether mixture (K ₂ CO ₃ /18-crown-6) are preferably used (Non-Patent Document 2). Furthermore, when the acyloxysilane is Me ₃ Si—OCOC ₆ F ₅ , KF or CsF is preferably used in a dimethylformamide solvent (Patent Document 2), and when the acyloxysilane is Me ₃ Si—OCOCF ₃ , potassium trifluoroacetate is preferably used in a dimethylformamide solvent (Patent Document 3).

U.S. Pat. No. 6,160,151 Russian Patent Application Publication No. 20130111741 French Patent Application Publication No. 2862972

4th Edition, Experimental Chemistry Lectures, Vol. 24, p. 122, Maruzen (1992) H. H. Hergott, G. Simchen, Synthesis, 626-627 (1980) A. N. Kornev, O. S. Donnikova, V. V. Semenov, Yu. A. Kurskii, Russ. Chem. Bull. , 44, 145-148 (1995)

However, with regard to the conventional methods, method (A) (1) requires the use of organometallic compounds that are highly reactive to water or moisture and therefore difficult and dangerous to handle;
(2) the production costs of organometallic compounds are generally high, and (3) a large amount of metal chlorides is produced as a by-product.
Furthermore, method (B) has the following problems: (1) the activity of previously known reaction accelerators is insufficient, so that applicable acyloxysilanes are limited to certain types; (2) the yield of the product is low; (3) the reaction system is homogeneous, so that the reaction accelerator cannot be separated and recovered by simple techniques such as filtration and centrifugation; and (4) when dimethylformamide solvent is used, dimethylformamide is a hazardous substance, so that the impact on the environment and health must be taken into consideration (the Ministry of Health, Labor and Welfare of Japan has established "control concentrations" as an index for evaluating the state of the working environment regarding certain hazardous substances. The concentration of the hazardous substance in the workplace is required to be below the control concentration. The control concentration for dimethylformamide is 10 ppm.).
For these reasons, there is a demand for an industrially advantageous method that can solve the problems of the conventional techniques.

The present invention was made in consideration of the above circumstances, and aims to provide a method for producing carbosilanes having Si-C bonds more safely and efficiently.

As a result of intensive research conducted by the inventors to solve the above problems, they discovered that the production of carbosilanes having Si-C bonds by decarboxylation of acyloxysilanes (1) proceeds efficiently in the presence of a base catalyst whose conjugate acid has a pKa in a specific range, (2) proceeds efficiently with acyloxysilanes having a specific structure, and (3) proceeds efficiently in a reaction system in which the calculated energy difference between the starting system and the product system is equal to or less than a certain value, and thus completed the present invention.

That is, this application provides the following inventions.
<1>
A method for producing a carbosilane having an Si-R bond, comprising a decarboxylation reaction step of carrying out decarboxylation in the presence of a base catalyst from an acyloxysilane having an Si-OCOR bond (OCO represents an oxycarbonyl group, O-C(=O), and R represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group may be substituted with groups that do not participate in the reaction), the method satisfying any one of the following conditions (1) to (3) and optionally including a pre-step of forming an acyloxysilane:
(1) The base catalyst is a compound having a conjugate acid with a pKa in the range of 8 to 50; a phosphazene compound; a bicyclic amine compound; a guanidine compound; an amidine compound; or an organic polymer compound or an inorganic compound having a group derived from any of these compounds.
(2) R in the Si—OCOR bond is an alkyl group or an aryl group in which some or all of the hydrogen atoms bonded to carbon atoms are substituted with halogen atoms, nitro groups, or cyano groups; or an alkynyl group.
(3) The calculated energy difference ΔU in the reaction in which carbosilane is produced by decarboxylation of the acyloxysilane (the calculated energy difference ΔU indicates the energy difference between the source system and the product system (the total internal energy of the product system molecules−the internal energy of the source system molecules) calculated using a density functional method (calculation level of B3LYP/6-31G ^** )) is 20 kcal/mol or less.
＜2＞
The method according to <1>, wherein the pre-step is any one of the following steps (4) to (6), and the pre-step and the subsequent decarboxylation step are carried out continuously.
(4) A step of forming the acyloxysilane having the Si-OCOR bond by reacting an alkoxysilane having a Si-OR' bond (R' represents a hydrocarbon group having 1 to 3 carbon atoms) with a carboxylic anhydride represented by (RCO) _2O (R is as defined above).
(5) A step of forming the acyloxysilane having the Si-OCOR bond by reacting an allylsilane having a Si-R″ bond (R″ represents an allyl group) with a carboxylic acid represented by RCO ₂ H (R has the same meaning as defined above).
(6) A step of forming the acyloxysilane having a Si-OCOR bond by reacting a chlorosilane having a Si-Cl bond with a carboxylic acid represented by RCO ₂ H (R has the same meaning as defined above).
＜3＞
The base catalyst is 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ⁵ ,4λ ⁵ -catenadi(phosphazene) (P2-t-Bu), 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ ⁵ ,4λ ⁵ 4-catenadi(phosphazene) (P4-t-Bu), 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP), tert-butylimino-tri(pyrrolidino)phosphorane (BTPP), 1-azabicyclo[2.2.2]octane (ABCO), 1,4-diazabicyclo[2.2.2]octane (DABCO), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), or an organic polymer having a group derived therefrom.
＜4＞
The method according to any one of <1> to <3>, wherein the acyloxysilane having a Si—OCOR bond is an acyloxysilane selected from the following general formulas (IA) to (ID):
^{R1aR2bR3cSi ( OCOR} _{) d ( IA} )
_RCO2 ( ^{SiR4R5 )} _m1OCOR (IB)
_RCO2 ( ^{SiR6R7O )} _m2 (COR)(IC)
₍ ^{R8eR9fR10gSiOCO} ₎ ^hR11 ₍ ^{ID )} _​
(In these formulas, a, b, and c are each independently 0 or 1; d is an integer of 1 to 3; a+b+c+d=4; m1 and m2 are each independently an integer of 2 or greater; R has the same meaning as defined above; R ¹ to R ¹⁰ are each independently a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a halogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group or the alkoxy group may be substituted with groups that do not participate in the reaction; e, f, and g are each independently 0 or 1; e+f+g=3; h is an integer of 2 to 4; R ¹¹ is an h-valent hydrocarbon group having 1 to 20 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the h-valent hydrocarbon group may be substituted with groups that do not participate in the reaction.)

The present invention has the effect of producing carbosilanes having Si-C bonds more safely and efficiently than conventional methods.

In detail, the method for producing a carbosilane having a Si-C bond according to one embodiment of the present invention (hereinafter sometimes abbreviated as "the production method according to this embodiment") has the following features.
(1) The raw materials and base are easy to handle and highly safe.
(2) The reaction system does not produce large amounts of waste materials such as salts.
(3) When a solid base is used, the base can be easily separated and recovered.
The manufacturing method of the present invention enables improved safety and efficiency in the manufacturing process, and is believed to have significant advantages over conventional techniques in terms of economy and low environmental impact.

The present invention will be described in detail below. Unless otherwise specified, when a symbol in a formula in this specification is used in other formulas, the same symbol has the same meaning.
The production method according to this embodiment is a method for producing a carbosilane having a Si-R bond, comprising a decarboxylation reaction step of carrying out decarboxylation in the presence of a base catalyst from an acyloxysilane having a Si-OCOR bond (OCO represents an oxycarbonyl group, O-C(=O); R represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom; some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group may be substituted with groups that are not involved in the reaction).
In this specification, the term "group not involved in the reaction" refers to a group that does not exhibit the reaction activity of a decarboxylation reaction, or the reaction activity of a decarboxylation reaction and an acyloxysilane-forming reaction described below, and does not adversely affect these reactions.

In this embodiment, examples of acyloxysilanes that can be used as a raw material include acyloxysilanes represented by the following general formulas (IA) to (ID).
^{R1aR2bR3cSi ( OCOR} _{) d ( IA} )
_RCO2 ( ^{SiR4R5 )} _m1OCOR (IB)
_RCO2 ( ^{SiR6R7O )} _m2 (COR)(IC)
₍ ^{R8eR9fR10gSiOCO} ₎ ^hR11 ₍ ^{ID )} _​

In these formulas, a, b, and c are each independently 0 or 1; d is an integer of 1 to 3; a+b+c+d=4. Moreover, m1 and m2 are each independently an integer of 2 or more. R has the same meaning as above. R ¹ to R ¹⁰ are each independently a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a halogen atom, and some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group or the alkoxy group may be substituted with a group that does not participate in the reaction. e, f, and g are each independently 0 or 1; e+f+g=3. h is an integer of 2 to 4. R ¹¹ is an h-valent hydrocarbon group having 1 to 20 carbon atoms, and some or all of the hydrogen atoms bonded to the carbon atoms of the h-valent hydrocarbon group may be substituted with a group that does not participate in the reaction.

Specific examples of the hydrocarbon group represented by R ¹ to R ¹⁰ include an alkyl group, an aryl group, an aralkyl group, an alkenyl group, and an alkynyl group.
When the hydrocarbon group is an alkyl group, the number of carbon atoms in the alkyl group is preferably 1 to 16, more preferably 1 to 12. A part or all of the hydrogen atoms bonded to the carbon atoms of the alkyl group may be substituted with groups that do not participate in the reaction.

Specific examples of the group that is not involved in the reaction include an alkoxy group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 1 to 6 carbon atoms, a halogen atom, etc. More specific examples of the alkoxy group, alkoxycarbonyl group, and halogen atom include alkoxy groups such as a methoxy group, an ethoxy group, and a hexoxy group; alkoxycarbonyl groups such as a methoxycarbonyl group and a propoxycarbonyl group; and halogen atoms such as a fluorine atom and a chlorine atom.
Specific examples of the alkyl group which may be substituted with a group which does not participate in the reaction include a methyl group, an ethyl group, a propyl group, a butyl group, a sec-butyl group, a pentyl group, a hexyl group, a cyclohexyl group, an octyl group, a decyl group, a 2-methoxyethyl group, a 3-ethoxypropyl group, a 2-methoxycarbonylethyl group, a trifluoromethyl group, and a 3-chloropropyl group.

In addition, when the hydrocarbon group is an aryl group, a monovalent aromatic organic group of a hydrocarbon ring system or a heterocyclic ring system can be used. When the aryl group is a hydrocarbon ring system, the number of carbon atoms of the hydrocarbon ring system is preferably 6 to 18, more preferably 6 to 14. Specific examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a pyrenyl group. In addition, when the aryl group is a heterocyclic ring system, the heteroatom in the heterocyclic ring is a sulfur atom, an oxygen atom, or the like. In addition, the number of carbon atoms of the aryl group is preferably 4 to 12, more preferably 4 to 8. Specific examples of the aryl group include a thienyl group, a benzothienyl group, a dibenzothienyl group, a furyl group, a benzofuryl group, and a dibenzofuryl group.
A part of the hydrogen atoms of the aryl group may be substituted with a group that does not participate in the reaction. Specific examples of the group that does not participate in the reaction include those shown in the case of the alkyl group above. In addition, other groups that do not participate in the reaction include an oxyethylene group, an oxyethyleneoxy group, etc., which are divalent groups that bond two carbon atoms on a ring.
Specific examples of the aryl group substituted with a group that does not participate in the reaction include a methylphenyl group, an ethylphenyl group, a hexylphenyl group, a methoxyphenyl group, an ethoxyphenyl group, a butoxyphenyl group, an octoxyphenyl group, a methyl(methoxy)phenyl group, a fluoro(methyl)phenyl group, a chloro(methoxy)phenyl group, a bromo(methoxy)phenyl group, a 2,3-dihydrobenzofuranyl group, and a 1,4-benzodioxanyl group.

Furthermore, when the hydrocarbon group is an aralkyl group, the number of carbon atoms in the aralkyl group is preferably 7 to 19, more preferably 7 to 15. Some or all of the hydrogen atoms bonded to the carbon atoms of the aralkyl group may be substituted with a group that does not participate in the reaction. Specific examples of the group that does not participate in the reaction include those listed above for the alkyl group.
Specific examples of the aralkyl group which may be substituted by a group which does not participate in the reaction include a benzyl group, a phenethyl group, a 2-naphthylmethyl group, a 9-anthrylmethyl group, a (4-chlorophenyl)methyl group, and a 1-(4-methoxyphenyl)ethyl group.

When the hydrocarbon group is an alkenyl group, the number of carbon atoms in the alkenyl group is preferably 2 to 18, more preferably 2 to 14. Some or all of the hydrogen atoms bonded to the carbon atoms of the alkenyl group may be substituted with a group that does not participate in the reaction. Specific examples of the group that does not participate in the reaction include those shown above in the case of the alkyl group, as well as the aryl group shown above.
Specific examples of the alkenyl group which may be substituted by a group which does not participate in the reaction include a vinyl group, a 2-propenyl group, a 3-butenyl group, a 5-hexenyl group, a 9-decenyl group, a 2-phenylethenyl group, a 2-(methoxyphenyl)ethenyl group, a 2-naphthylethenyl group, and a 2-anthrylethenyl group.

When the hydrocarbon group is an alkynyl group, the number of carbon atoms in the alkynyl group is preferably 2 to 18, more preferably 2 to 16. Some or all of the hydrogen atoms bonded to the carbon atoms of the alkynyl group may be substituted with a group that does not participate in the reaction. Specific examples of the group that does not participate in the reaction include those shown above in the case of the alkyl group, as well as the aryl group shown above.
Specific examples of the alkynyl group which may be substituted by a group which does not participate in the reaction include a phenylethynyl group, a 1-propynyl group, and a 3-phenyl-1-propynyl group.

On the other hand, when R ¹ to R ¹⁰ are alkoxy groups, the number of carbon atoms in the alkoxy groups is preferably 1 to 16, more preferably 1 to 12. Some or all of the hydrogen atoms bonded to the carbon atoms of the alkoxy groups may be substituted with groups that do not participate in the reaction. Specific examples of groups that do not participate in the reaction include those listed above for the alkyl groups.
Specific examples of the alkoxy group which may be substituted with a group which does not participate in the reaction include a methoxy group, an ethoxy group, a tert-butoxy group, and a cyclohexoxy group.

When R ¹ to R ¹⁰ are halogen atoms, the halogen atoms are fluorine, chlorine, bromine, or the like, preferably fluorine or chlorine, more preferably chlorine.

R ¹¹ represents an h-valent hydrocarbon group having 1 to 20 carbon atoms. The h-valent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹¹ is a linking group in which h hydrogen atoms have been removed from an alkane, aromatic ring, or the like having 1 to 20 carbon atoms. The number of carbon atoms in the h-valent hydrocarbon group is preferably 1 to 16, and more preferably 1 to 12. The hydrogen atom bonded to the carbon atom of the h-valent hydrocarbon group may be substituted with a group that is not involved in the reaction.
Here, h is an integer of 2 to 4, and preferably 2.

When the h-valent hydrocarbon group is an aliphatic linking group obtained by removing h hydrogen atoms from an alkane, the number of carbon atoms in the alkane is preferably 1 to 16, more preferably 1 to 12. Some or all of the hydrogen atoms bonded to the aliphatic linking group obtained by removing h hydrogen atoms from an alkane may be substituted with a group that does not participate in the reaction. Specific examples of the group that does not participate in the reaction include those shown for the alkyl groups represented by R ¹ to R ¹⁰ .
Specific aliphatic linking groups include groups in which h hydrogen atoms have been removed from methane, ethane, propane, butane, pentane, hexane, cyclohexane, octane, decane, methoxyethane, ethoxypropane, methoxycarbonylethane, difluoromethane, chloropropane, and the like.

When the h-valent hydrocarbon group is an aromatic linking group in which h hydrogen atoms have been removed from an aromatic ring, the aromatic ring is an aromatic hydrocarbon ring or an aromatic heterocycle.
In the case of an aromatic hydrocarbon ring, the number of carbon atoms in the aromatic hydrocarbon ring is preferably 6 to 18, more preferably 6 to 14. Specific examples of the aromatic hydrocarbon ring include benzene, naphthalene, anthracene, phenanthrene, pyrene, and the like.
When the aromatic ring is an aromatic heterocycle, the heteroatom in the aromatic heterocycle is a sulfur atom, an oxygen atom, or the like. The number of carbon atoms in the aromatic heterocycle is preferably 4 to 12, and more preferably 4 to 8. Specific examples of the aromatic heterocycle include thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, and the like.
A part or all of the hydrogen atoms bonded to the aromatic linking group obtained by removing h hydrogen atoms from the aromatic ring may be substituted with a group that does not participate in the reaction. Specific examples of the group that does not participate in the reaction include those shown in the case of the alkyl groups represented by R ¹ to R ^10. Other examples of the group that does not participate in the reaction include an oxyethylene group, an oxyethyleneoxy group, etc., which are divalent groups that bond two carbon atoms on an aromatic ring.
Specific examples of the aromatic linking group include groups in which h hydrogen atoms have been removed from benzene, methylbenzene, ethylbenzene, hexylbenzene, methoxybenzene, ethoxybenzene, butoxybenzene, octoxybenzene, methyl(methoxy)benzene, fluoro(methyl)benzene, chloro(methoxy)benzene, bromo(methoxy)benzene, 2,3-dihydrobenzofuran, 1,4-benzodioxane, and the like.

Furthermore, R represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom, and when R is a hydrocarbon group, the number of carbon atoms in the hydrocarbon group is preferably 1 to 16, more preferably 1 to 12. The hydrogen atom bonded to the carbon atom of the hydrocarbon group may be substituted with a group that does not participate in the reaction.
Specific examples of the group that does not participate in the reaction include those given in the case of the alkyl groups represented by R ¹ to R ¹⁰ .
Examples of the hydrocarbon group represented by R include an alkyl group, an aryl group, an aralkyl group, an alkenyl group, and an alkynyl group. Specific examples of these groups include the above-mentioned R ¹ to R ¹⁰
Examples of the substituent include those shown in the description of the group.

Among these groups, in terms of reactivity, R is preferably an alkyl group or aryl group in which the hydrogen atom bonded to the carbon atom is substituted with a halogen atom, a nitro group, or a cyano group, or an alkynyl group. As the halogen atom, a fluorine atom, a chlorine atom, or a bromine atom is preferred, and a fluorine atom or a chlorine atom is more preferred.

Specific examples of these groups include a trifluoromethyl group, a difluoromethyl group, a fluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, a trichloromethyl group, a dichloromethyl group, a chloromethyl group, a pentachloroethyl group, a nitromethyl group, a cyanomethyl group, a pentafluorophenyl group, a tetrafluorophenyl group, a trifluorophenyl group, a difluorophenyl group, a fluorophenyl group, a pentachlorophenyl group, a tetrachlorophenyl group, a trichlorophenyl group, a dichlorophenyl group, a chlorophenyl group, a nitrophenyl group, a cyanophenyl group, an ethynyl group, a propynyl group, and a phenylethynyl group.

m1 and m2 are each independently an integer of 2 or more, and the upper limit is not particularly limited as long as it does not impair the effects of the present invention, but is usually 2000 or less, preferably 1000 or less. It is particularly preferable that m1 and m2 are 2, that is, it is particularly preferable that the acyloxysilanes represented by formula (IB) and formula (IC) are disilane and disiloxane having two acyloxy groups, respectively.

From the above, specific examples of the acyloxysilane of the general formula (IA) include trimethyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMe ₃ ), dimethylbis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ SiMe ₂ ), methyltris(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₃ SiMe ), tetrakis(pentafluorophenylcarbonyloxy)silane ((C 6 F ₅ CO ₂ ) ₄ Si), tri(ethoxy)(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )Si(OEt) ₃ ), di(ethoxy)bis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ SiMe 2 ) _. Si(OEt) ₂ ), tri(methoxy)(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )Si(OMe) ₃ ), di(methoxy)bis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ Si(OMe) ₂ ), trichloro(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiCl ₃ ), dichlorobis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ SiCl ₂ ), trimethyl(2,3,5,6-tetrafluorophenylcarbonyloxy)silane ((2,3,5,6-F ₄ C ₆ HCO ₂ )SiMe ₃ ), trimethyl(2,4,6-trifluorophenylcarbonyloxy)silane ((2,4,6-F ₃ C ₆ H ₂ CO ₂ SiMe ₃ ), trimethyl(2,6-difluorophenylcarbonyloxy)silane ((2,6-F ₂ C ₆ H ₃ CO ₂ )SiMe ₃ ), trimethyl(2-fluorophenylcarbonyloxy)silane ((2-FC ₆ H ₄ CO ₂ )SiMe ₃ ), trimethyl(2,4,6-trichlorophenylcarbonyloxy)silane ((2,4,6-Cl ₃ C ₆ H ₂ CO ₂ )SiMe ₃ ), trimethyl(2,6-dichlorophenylcarbonyloxy)silane ((2,6-Cl ₂ C ₆ H ₃ CO ₂ )SiMe ₃ ), trimethyl(2-chlorophenylcarbonyloxy)silane ((2-ClC ₆ H ₄ CO ₂ )SiMe ₃ ), trimethyl(3,4,5,6-tetrafluoro-2-nitrophenylcarbonyloxy)silane ([2-(O ₂ N)C ₆ F ₄ CO ₂ ]SiMe ₃ ), trimethyl(2-nitrophenylcarbonyloxy)silane ([2-(O ₂ N)C ₆ H ₄ CO ₂ ]SiMe ₃ ), trimethyl(2-cyanophenylcarbonyloxy)silane ([2-(NC)C ₆ H ₄ CO ₂ ]SiMe ₃ ), dimethylphenyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )S
iMe ₂ Ph), dimethyl(pentafluorophenylcarbonyloxy)(vinyl)silane ((C ₆ F ₅ CO ₂ )SiMe ₂ (CH═CH ₂ )), (3-cyanopropyl)dimethyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMe ₂ [(CH ₂ ) ₃ CN]), trimethyl(trifluoroacetyloxy)silane ((CF ₃ CO ₂ )SiMe ₃ ), dimethylbis(trifluoroacetyloxy)silane ((CF ₃ CO ₂ ) ₂ SiMe ₂ ), tri(ethoxy)(trifluoroacetyloxy)silane ((CF ₃ CO ₂ )Si(OEt) ₃ ), di(methoxy)bis(trifluoroacetyloxy)silane ((CF ₃ CO ₂ ) ₂ Si(OMe) ₂ ), trichloro(trifluoroacetyloxy)silane ((CF ₃ CO ₂ )SiCl ₃ ), trimethyl(pentafluoropropionyloxy)silane ((CF ₃ CF ₂ CO ₂ )SiMe ₃ ), trimethyl(trichloroacetyloxy)silane ((CCl ₃ CO ₂ )SiMe ₃ ), (ethoxy)dimethyl(trichloroacetyloxy)silane ((CCl ₃ CO ₂ )SiMe ₂ (OEt)), di(ethoxy)methyl(trichloroacetyloxy)silane ((CCl ₃ CO ₂ )SiMe(OEt) ₂ ), tri(ethoxy)(trichloroacetyloxy)silane ((CCl ₃ CO ₂ )Si(OEt) ₃ ), trichloro(trichloroacetyloxy)silane ((CCl ₃ CO ₂ )SiCl ₃ ), dichlorobis(trichloroacetyloxy)silane ((CCl ₃ CO ₂ ) ₂ SiCl ₂ ), trimethyl(dichloroacetyloxy)silane ((CHCl ₂ CO ₂ )SiMe ₃ ), trimethyl(chloroacetyloxy)silane ((CH ₂ ClCO ₂ )SiMe ₃ ), trimethyl(chlorodifluoroacetyloxy)silane ((CClF ₂ CO ₂ )SiMe ₃ ), trimethyl(tribromoacetyloxy)silane ((CBr ₃ CO ₂ )SiMe ₃ ), trimethyl(phenylethynylcarbonyloxy)silane ((PhC≡C)CO ₂ SiMe ₃ ), trimethyl(1-propynylcarbonyloxy)silane ((MeC≡C)CO ₂ SiMe ₃ ), and the like.

On the other hand, specific examples of the acyloxysilane of general formula (IB) include 1,1,2,2-tetramethyl-1,2-bis(pentafluorophenylcarbonyloxy)disilane ((C ₆ F ₅ CO ₂ )SiMe ₂ SiMe ₂ (OCOC ₆ F ₅ )), 1,1,2,2,3,3-hexamethyl-1,3-bis(pentafluorophenylcarbonyloxy)trisilane ((C ₆ F ₅ CO ₂ )SiMe ₂ SiMe ₂ SiMe ₂ (OCOC ₆ F ₅ )), and the like.

Specific examples of the acyloxysilane of general formula (IC) include 1,1,3,3-tetramethyl-1,3-bis(pentafluorophenylcarbonyloxy)disiloxane ((C ₆ F ₅ CO ₂ )SiMe ₂ OSiMe ₂ (OCOC ₆ F ₅ )), 1,1,3,3,5,5-hexamethyl-1,5-bis(pentafluorophenylcarbonyloxy)trisiloxane ((C ₆ F ₅ CO ₂ )SiMe ₂ OSiMe ₂ OSiMe ₂ (OCOC ₆ F ₅ )), and the like.

Specific examples of the acyloxysilane of general formula (ID) include 2,4,5,6-tetrafluoro-1,3-bis(trimethylsiloxycarbonyl)benzene (1,3-C ₆ F ₄ (CO ₂ SiMe ₃ ) ₂ ), 2,3,5,6-tetrafluoro-1,4-bis(trimethylsiloxycarbonyl)benzene (1,4-C ₆ F ₄ (CO ₂ SiMe ₃ ) ₂ ), and the like.

Furthermore, as the acyloxysilane used in the production method according to this embodiment, an acyloxysilane having a calculated energy difference ΔU of 20 kcal/mol or less in the reaction in which carbosilane is produced by decarboxylation from acyloxysilane is also preferably used. The upper limit of ΔU is preferably 18 kcal/mol or less, more preferably 16 kcal/mol or less, and the lower limit of ΔU is not particularly limited, but is usually 1 kcal/mol or more. The decarboxylation reaction from acyloxysilane is a thermodynamic endothermic reaction because the total internal energy of the molecules in the product system is higher than the internal energy of the molecules in the starting system, and is a reaction that requires external energy supply by heating or the like. However, since ΔU is within the above range, the energy required for the reaction becomes sufficiently small, and it is considered that the decarboxylation reaction can proceed even at a heating temperature of about 300° C. or less.
Here, the calculated energy difference ΔU refers to the calculated energy difference between the original system and the product system using density functional theory (calculation level of B3LYP/6-31G ^** ) (energy obtained by subtracting the internal energy of the original molecule, acyloxysilane, from the sum of the internal energies of the product molecules, carbosilane and _CO2 , = U (internal energy of carbosilane) + U (internal energy of _CO2 ) - U (internal energy of acyloxysilane)).

When the acyloxysilane is a monosilane having one or more acyloxy groups, specific examples thereof include (the number in the brackets indicates the calculated value of ΔU (kcal/mol). When there are multiple acyloxy groups, the calculated value when one acyloxy group undergoes a decarboxylation reaction is shown.), (ethynylcarbonyloxy)trichlorosilane ((HC≡CCO ₂ )SiCl ₃ ) [0.67], (1,3-butadiynylcarbonyloxy)trimethylsilane ((HC≡CC≡CCO ₂ )SiCl ₃ ) [4.81], (ethynylcarbonyloxy)trimethylsilane ((HC≡CCO ₂ )SiMe ₃ ) [5.72], tetrakis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₄ Si) [6.18], dichlorobis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ SiCl ₂ ) [6.19], bis(pentafluorophenyl)bis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ Si(C ₆ F ₅ ) ₂ ) [6.38], (dicyanomethylcarbonyloxy)trimethylsilane ([(NC) ₂ CHCO ₂ ]SiMe ₃ ) [6.47], trimethyl(1-propynylcarbonyloxy)silane ((MeC≡CCO ₂ )SiMe ₃ ) [6.57], trichloro(cyanomethylcarbonyloxy)silane ((NCCH ₂ CO ₂ )SiCl ₃ ) [6.67], trimethyl(phenylethynylcarbonyloxy)silane ((PhC≡CCO ₂ )SiMe ₃ ) [6.76], trichloro(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiCl ₃ ) [7.27], (trichloromethylcarbonyloxy)trichlorosilane ((CCl ₃ CO ₂ )SiCl ₃ ) [7.28], acetoxytrichlorosilane ((MeCO ₂ )SiCl ₃ ) [7.79], methyltris(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMe) [7.96], (benzylcarbonyloxy)trichlorosilane ((PhCH ₂ CO ₂ )SiCl ₃ ) [8.08], trichloro(nitromethylcarbonyloxy)silane ((O ₂ NCH ₂ CO ₂ )SiCl ₃ ) [8.17], trichloro(methoxycarbonylmethylcarbonyloxy)silane ((MeOCOCH ₂ CO ₂ )SiCl ₃ ) [8.24], methyl(pentafluorophenyl)bis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ SiMe(C ₆ F ₅ )) [8.55], diacetoxydichlorosilane ((MeCO ₂ )SiCl ₂ ) [8.56], (allylcarbonyloxy)trichlorosilane ((CH ₂ ═CHCH ₂ CO ₂ )SiCl ₃ ) [8.58], (tribromomethylcarbonyloxy)trimethylsilane ((CBr ₃ CO ₂ )SiMe ₃ ) [8.64], dimethylbis(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₂ SiMe ₂ ) [8.73], (pentafluorophenyl)tris(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ ) ₃ Si(C ₆ F ₅ )) [8.92], triethyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiEt ₃ ) [8.96], triethyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiEt ₃ ) [8.96], dichloro(pentafluorophenyl)(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiCl ₂ (C ₆ F ₅ ) [8.98], dimethyl(pentafluorophenylcarbonyloxy)vinylsilane ₍ (C6F5CO2) _SiMe2Vi ) [8.99] _, chlorodimethyl( _{pentafluorophenylcarbonyloxy} )silane ((C6F5CO2) _SiClMe2 ) [9.00] _, trimethyl(trichloromethylcarbonyloxy)silane ((CCl3CO2) _SiMe3 ) [9.00] _, trichloro ₍ chloromethylcarbonyloxy)silane ((ClCH2CO2)SiCl3) [ _9.18 ] _, dimethyl ₍ pentafluorophenyl) ₍ pentafluorophenylcarbonyloxy)silane ((C6F5CO2) _{SiMe2 ( C6F5 )} ) _[ 9.26] _, triacetoxy(trichloromethylcarbonyloxy)silane (( _{Cl 3CCO2 )} Si(OCOMe) _{3 ) [} 9.43], trimethyl(tetrafluoro-4-pyridylcarbonyloxy)silane ((4- _C5F4NCO2 ) _SiMe3 ) [9.44], acetoxytrifluorosilane (( _MeCO2 ) _SiF3 ) [9.82], (3 _- cyanopropyl)dimethyl(pentafluorophenylcarbonyloxy)silane ((C6F5CO2) _SiMe2 [( _CH2 ) _3CN ]) [10.01], tris(pentafluorophenyl) _{( pentafluorophenylcarbonyloxy} )silane ( _{( C6F5CO2 )} Si( _C6F5 ) ₃ ) _[ 10.01], trichloro(trifluoromethylcarbonyloxy)silane (( _{CF3CO2 )} SiCl ₃ ) [10.03], dimethylphenyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMe ₂ Ph) [10.10], trimethyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMe ₃ ) [10.10], trimethoxy(pentafluorophenylcarboyloxy)silane ((C ₆ F ₅ CO ₂ )Si(OMe) ₃ ) [10.13], methylbis(pentafluorophenyl)(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMe(C ₆ F ₅ ) ₂ ) [10.14], trimethyl(nitromethylcarbonyloxy)silane ([CH ₂ (NO ₂ )CO ₂ ]SiMe ₃ ) [10.29], trimethyl(2,3,5,6-tetrafluorophenylcarbonyloxy)silane ((2,3,5,6-C ₆ F ₄ HCO ₂ )SiMe ₃ ) [10.34], trimethyl(trifluoromethylsulfonylmethylcarbonyloxy)silane ((CF ₃ SO ₂ CH ₂ CO ₂ )SiMe ₃ ) [10.36], trichloro(propionyloxy)silane ((EtCO ₂ )SiCl ₃ ) [10.52], trichloro(methoxymethylcarbonyloxy)silane ((MeOCH ₂ CO ₂ )SiCl ₃ [10.70], trimethoxy(trichloromethylcarbonyloxy)silane ((CCl ₃ CO ₂ )Si(OMe) ₃ ) [10.78], trichloro(2-propylcarbonyloxy)silane ((2-PrCO ₂ )SiCl ₃ ) [10.95], diacetoxydifluorosilane ((MeCO ₂ ) ₂ SiF ₂ ) [11.07], methyldiphenyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMePh ₂ ) [11.23], acetoxydichloromethylsilane ((MeCO ₂ )SiCl ₂ Me) [11.31], trimethyl(2,4,6-trifluorophenylcarbonyloxy)silane ((2,4,6-C ₆ F ₃ H ₂ CO ₂ )SiMe ₃ ) [11.44], trimethyl(6-nitrotetrafluorophenylcarbonyloxy)silane ([6-(O ₂ N)C ₆ F _4CO2SiMe3 ) [ _11.64 ], trimethyl(2,6- _{difluorophenylcarbonyloxy)silane ((2,6-C6F2H3CO2)SiMe3) [11.66], tetraacetoxysilane ((MeCO2)4Si ) [ 11.77 ] , trimethyl (} methylsulfonylmethylcarbonyloxy)silane ((MeSO2CH2CO2)SiMe3) _[ 11.88], trimethyl(phenylsulfonylmethylcarbonyloxy)silane ((PhSO2CH2CO2 _{) SiMe3} ) [11.94], trichloro ₍ formyloxy ₎ silane (( _HCO2 ) _SiCl3 ) [ _{12.01 ] ,} acetoxydichloromethylsilane (( _MeCO2 ) _SiCl2 Me) [12.04], trimethyl(cyanomethylcarbonyloxy)silane (NCCH ₂ CO ₂ )SiMe ₃ ) [12.16], (tert-butylcarbonyloxy)trichlorosilane ((tert-BuCO ₂ )SiCl ₃ ) [12.29], ethoxydimethyl(trichloroacetyloxy)silane ((CCl ₃ CO ₂ )SiMe ₂ (OEt)) [12.38], trimethyl(dichloroacetoxy)silane ((CCl ₂ HCO ₂ )SiMe ₃ ) [12.54], trimethyl(chlorodifluoroacetoxy)silane ((CClF ₂ CO ₂ )SiMe ₃ ) [12.83], trimethyl(heptafluoropropylcarbonyloxy)silane ((CF ₃ CF ₂ CF ₂ CO ₂ )SiMe ₃ ) [12.84], trimethyl(tetrafluoro-2-pyridylcarbonyloxy)silane ((2-C ₅ F ₄ NCO ₂ )SiMe ₃ ) [13.1
8], trimethyl(pentafluoroethylcarbonyloxy)silane ((CF ₃ CF ₂ CO ₂ )SiMe ₃ ) [13.19], trichloro(4-pyridylcarbonyloxy)silane ((4-PyCO ₂ )SiCl ₃ ) [13.22],
Trimethyl(nonafluorobutylcarbonyloxy)silane ((CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ )SiMe ₃ ) [13.22], dichlorobis(formyloxy)silane ((HCO ₂ )SiCl ₂ ) [13.33], trichloro(vinylcarbonyloxy)silane ((CH ₂ ═CHCO ₂ )SiCl ₃ ) [13.40], trimethyl(trifluoroacetoxy)silane ((CF ₃ CO ₂ )SiMe ₃ ) [13.56], trichloro(benzoyloxy)silane ((PhCO ₂ )SiCl ₃ ) [13.84], trimethyl(2-nitrophenylcarbonyloxy)silane ([2-(O ₂ N)C ₆ H ₄ CO ₂ ]SiMe ₃ ) [13.86], trichloro(2-pyridylcarbonyloxy)silane ((2-PyCO ₂ )SiCl ₃ ) [13.93], trimethyl(pentafluoro-2-propenylcarbonyloxy)silane ((CF ₂ ═CFCF ₂ CO ₂ )SiMe ₃ ) [14.13], dichloro(formyloxy)silane ((HCO ₂ )SiHCl ₂ ) [14.30], dichloro(formyloxy)methylsilane ((HCO ₂ )SiCl ₂ Me) [14.55], bis(benzoyloxy)dichlorosilane ((PhCO ₂ ) ₂ SiCl ₂ ) [14.97], (acetoxy)chlorodimethylsilane ((MeCO ₂ )SiClMe ₂ ) [15.10], acetoxydifluoromethylsilane ((MeCO ₂ )SiF ₂ Me) [15.11], (benzoyloxy)trifluorosilane ((PhCO ₂ )SiF ₃ ) [15.21], trimethyl(2,3,4,5-tetrafluorophenylcarbonyloxy)silane ((2,3,4,5-C ₆ F ₄ HCO ₂ )SiMe ₃ ) [15.63], (chloroacetoxy)trimethylsilane ((CClH ₂ CO ₂ )SiMe ₃ ) [16.07], (benzoyloxy)dichloromethylsilane ((PhCO ₂ )SiCl ₂ Me) [16.79], (2-fluorophenylcarbonyloxy)trimethylsilane ((2-C ₆ FH ₄ CO ₂ )SiMe ₃ ) [16.84], (2,4-difluorophenylcarbonyloxy)trimethylsilane ((2,4-C ₆ F ₂ H ₃ CO ₂ )SiMe ₃ ) [16.88], ((2,6-dichloro-4-pyridylcarbonyloxy)trimethylsilane ([4-(2,6-C ₅ Cl ₂ H ₃ N)CO ₂ ]SiMe ₃ ) [17.03], chloro(formyloxy)dimethylsilane ((HCO ₂ )SiClMe ₂ ) [17.19], (benzoyloxy)dichlorophenylsilane ((PhCO ₂ )SiCl ₂ Ph) [17.40], acetoxytrimethylsilane ((MeCO ₂ )SiMe ₃ ) [18.12], (4-chlorophenylcarbonyloxy)trimethylsilane ((4-ClC ₆ Examples _of the silanes include (benzylcarbonyloxy)trimethylsilane ((PhCH ₂ CO ₂ )SiMe ₃ ) [18.17], (benzylcarbonyloxy)trimethylsilane ((PhCH 2 CO 2 )SiMe ₃ ) [18.48], (2,6-dichlorophenylcarbonyloxy)trimethylsilane ((2,6-Cl ₂ C ₆ H ₃ CO ₂ )SiMe ₃ ) [18.50], trimethyl(pentachlorophenylcarbonyloxy)silane ((C ₆ Cl ₅ CO ₂ )SiMe ₃ ) [18.89], and (formyloxy)trimethylsilane ((HCO ₂ )SiMe ₃ ) [19.29].

In addition, when the acyloxysilane is a compound having two silicon atoms, specific examples of a compound having a ΔU of 20 kcal/mol or less (the number in brackets indicates the calculated value of ΔU (kcal/mol). In the case of a plurality of acyloxy groups, the calculated value is shown when one acyloxy group undergoes a decarboxylation reaction.) include 1,1,2,2-tetramethyl-1,2-bis(pentafluorophenylcarbonyloxy)disilane ((C ₆ F ₅ CO ₂ )Me ₂ SiSiMe ₂ (OCOC ₆ F ₅ )) [7.01], 1,1,2,2-tetramethyl-1-(pentafluorophenyl)-2-(pentafluorophenylcarbonyloxy)disilane ((C ₆ F ₅ )Me ₂ SiSiMe ₂ (OCOC ₆ F ₅ )) [9.82], 2,3,5,6-tetrafluoro-1,4-bis(trimethylsiloxycarbonyl)benzene (1,4-C ₆ F ₄ (CO ₂ SiMe ₃ ) ₂ ) [9.94], 1,1,3,3-tetramethyl-1,3-bis(pentafluorophenylcarbonyloxy)disiloxane ((C ₆ F ₅ CO ₂ )Me ₂ SiOSiMe ₂ (OCOC ₆ F ₅ )) [10.16], 2,4,5,6-tetrafluoro-1,3-bis(trimethylsiloxycarbonyl)benzene (1,3-C ₆ F ₄ (CO ₂ SiMe ₃ ) ₂ ) [10.52], 2,3,5,6-tetrafluoro-1-trimethylsilyl-4-(trimethylsiloxycarbonyl)benzene (1-Me ₃ Si-4-(Me ₃ SiOCO)C ₆ F ₄ ) [10.69], 1,1,3,3-tetramethyl-1-(pentafluorophenyl)-3-(pentafluorophenylcarbonyloxy)disiloxane ((C ₆ F ₅ )Me ₂ SiOSiMe ₂ (OCOC ₆ F ₅ )) [11.66], 2,4,5,6-tetrafluoro-1-trimethylsilyl-3-(trimethylsiloxycarbonyl)benzene (1-Me ₃ Si-3-(Me ₃ SiOCO)C ₆ F ₄ ) [11.73] and the like.

According to the manufacturing method of this embodiment, a carbosilane having an Si-C bond can be produced by carrying out a decarboxylation reaction in the presence of a specific base using an acyloxysilane having at least one acyloxy group as a raw material.

The decarboxylation reaction step in this embodiment is a step in which a carbosilane having an Si-C bond is produced by decarboxylation of the acyloxy group of an acyloxysilane. The reaction when the acyloxysilane is a monoacyloxysilane can be represented, for example, by the following scheme 1.

Furthermore, when a compound having a plurality of acyloxy groups is used as the acyloxysilane, unreacted acyloxy groups remain in the carbosilane produced by the reaction of one acyloxy group, and these may further react to give a carbosilane.
For example, as shown in Scheme 2 below, in the reaction of an acyloxysilane having two acyloxy groups (in Scheme 2, examples of acyloxysilane include monosilane, disilane, disiloxane, and disiloxycarbonyl compound), it is possible to produce a carbosilane ((A), (C), (E), or (G)) formed by the reaction of one acyloxy group, or a carbosilane ((B), (D), (F), or (H)) formed by the reaction of two acyloxy groups.

That is, in the decarboxylation reaction step in this embodiment, when a compound having multiple acyloxy groups is used as a raw material, a carbosilane formed by the reaction of one or multiple acyloxy groups can be produced. Therefore, the decarboxylation reaction step may be a step of obtaining a single type of carbosilane, or a step of obtaining a mixture of multiple types of carbosilane.

The production method according to this embodiment may also include a pre-step for forming an acyloxysilane. The pre-step may be, for example, any one of the following steps (4) to (6). In this embodiment, carbosilane can also be produced by continuously carrying out the pre-step and the subsequent decarboxylation reaction step.
(4) A process for forming an acyloxysilane having a Si-OCOR bond by reacting an alkoxysilane having a Si-OR' bond (R' represents a hydrocarbon group having 1 to 3 carbon atoms) with a carboxylic acid anhydride represented by (RCO) _2O (R is as defined above).
(5) A step of forming an acyloxysilane having a Si-OCOR bond by reacting an allylsilane having a Si-R″ bond (R″ represents an allyl group) with a carboxylic acid represented by RCO ₂ H (R has the same meaning as defined above).
(6) A step of forming an acyloxysilane having a Si-OCOR bond by reacting a chlorosilane having a Si-Cl bond with a carboxylic acid represented by RCO ₂ H (R has the same meaning as defined above).

Examples of hydrocarbon groups having 1 to 3 carbon atoms represented by R' include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, and vinyl groups.

For example, when the acyloxysilane is a monoacyloxysilane, as shown in the following scheme 3, in the previous step, the monoacyloxysilane can be formed from a monoalkoxysilane, a monoallylsilane, or a monochlorosilane. Then, in the decarboxylation reaction step, the generated monoacyloxysilane can be decarboxylated to produce a carbosilane.

In these pre-step reactions, a reaction promoter such as a catalyst is not necessarily required, but the reaction can be carried out using various reaction promoters.
For example, in (a) the reaction of a monoalkoxysilane with a carboxylic acid anhydride or (b) the reaction of a monoallylsilane with a carboxylic acid, an acid catalyst such as an inorganic or organic solid acid or Lewis acid can be used.
In the reaction (c) of chlorosilane with carboxylic acid, an organic or inorganic base can be used.

The pre-steps (4) to (6) can be carried out in accordance with conventionally known methods such as those shown in the following documents i to iii, respectively.
Reference i: International Publication No. 2016/143835 Reference ii: Tetrahedron Lett., 892-895 (1983)
References iii Gmelin Handbook: Si: M Vol. C, 69, 190-194
More specifically, as the inorganic or organic solid acid in the preceding steps (4) and (5), proton-type zeolite, cation exchange resin, or the like can be used, and as the Lewis acid, compounds such as iron(III) perchlorate, iron(III) chloride, and ruthenium(III) chloride (which may contain water of crystallization) can be used.
Furthermore, as the organic or inorganic base in the preceding step (6), triethylamine, N-methylpyrrolidine, pyridine, potassium carbonate, sodium carbonate, etc. can be used.
The specific reaction temperature and reaction time in the pre-processing steps (4) to (6) are about 0 to 200° C. and about 5 minutes to 6 hours.

In the pre-process of forming acyloxysilane, there is no need to isolate and purify the acyloxysilane, and it is possible to carry out the reaction in a one-pot process in combination with the decarboxylation process. In this way, by continuously carrying out the pre-process of producing acyloxysilane and the decarboxylation process of decarboxylation, carbosilane can be efficiently produced from alkoxysilane, etc., which is also a feature of the production method according to this embodiment.

In the decarboxylation reaction from acyloxysilane, the structure of R may be isomerized depending on the type of hydrocarbon group R of the acyloxy group (OCOR) or the type of base used.
For example, when R is a phenyl group having 1 to 4 substituents such as halogen atoms, an isomer in which the position of the halogen atoms on the phenyl group is changed may be produced in the decarboxylation reaction step.
That is, in the production method according to this embodiment, when a carbosilane having a Si-R bond is produced from an acyloxysilane having a Si-OCOR bond by a decarboxylation reaction step, if R is a phenyl group having 1 to 4 substituents such as halogen atoms, a mixture of structural isomers differing in the positions of the halogen atoms, etc. may be produced, and the carbosilane obtained by the production method according to this embodiment also includes a mixture of these structural isomers.

In the decarboxylation step in this embodiment, a base catalyst is used to promote the reaction.
The base catalyst includes a compound whose conjugate acid has a pKa in the range of 8 to 50. The pKa range of the compound is preferably 9 to 45, and more preferably 10 to 42.

The pKa of the conjugate acid is basically based on a value measured in water, but a value measured in an organic solvent such as acetonitrile can also be used.
Compounds having a conjugate acid with a pKa in the range of 8 to 50 include those disclosed in various conventionally known documents. Specific examples of such documents include the following reference documents (A) to (E).
(A) Chemistry Handbook Basics II (Revised 4th Edition), II-317, Maruzen, 1993
(B) J. Am. Che. Soc. , 79, 5441 (1957)
(C) Eur. J. Org. Chem., 4852 (2006)
(D)J. Org. Chem. , 70, 1019 (2005)
(E) Product description of phosphazene bases on the Merck website (https://www.sigmaaldrich.com/chemistry/chemical-synthesis/technology-spotlights/phosphazenes.html)

Therefore, specific examples of compounds with a conjugate acid pKa in the range of 8 to 50 (the numbers in parentheses indicate the pKa value of the conjugate acid in water and the symbol in the above literature, and * indicates the pKa value of the conjugate acid in acetonitrile) include triethylamine (10.72, A), diethylamine (10.98, B), dipropylamine (11.00, B), dibutylamine (11.25, B), diisopropylamine (11.05), diisobutylamine (10.50), tert-butylcyclohexylamine (11.23, B), benzylmethylamine (9.58, B), benzylethylamine (9.68, B), di-sec-butylamine (11.01 , B), dimethylethylamine (9.99, B), methyldiethylamine (10.29, B), dimethylpropylamine (9.99, B), dimethylbutylamine (10.02, B), dimethylisobutylamine (9.91, B), dimethylisopropylamine (10.30, B), dimethyl-sec-butylamine (10.40, B), dimethyl-tert-butylamine (10.52, B), tripropylamine (10.65, B), tributylamine (10.89, B), benzyldimethylamine (8.93, B), benzyldiethylamine (9.48, B), N-ethylpiperidine (10.40, B), N-methylpiperidine ( 10.08, B), N-methyltrimethyleneimine (10.40, B), N-methylpyrrolidine (10.46, B), 1-azabicyclo[2.2.2]octane (ABCO) (10.76, C), 1,4-diazabicyclo[2.2.2]octane (DABCO) (8.72, C), N,N,N',N'-tetramethylethylenediamine (TMEDA) (9.42, C), N,N,N',N'-tetramethyl-1,3-propanediamine (TMPDA) (9.81, C), 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) (24.34*, D), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (DBU) (24.34*, D), 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) (27.6*, E), tert-octyliminotris(dimethylamino)phosphorane (P1-t-Oct) (26.5*, E), 1-ethyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ^{5,4λ 5} -catenadi(phosphazene) (P2-Et) (32.9*, E), 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ^{5,4λ 5} -catenadi(phosphazene) (P2-t-Bu) (33.5*, E), 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ ^{5,4λ 5} -catenadi(phosphazene) (P4-t-Bu) (41.9 ^* , E), 1-tert-octyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ 5,4λ ⁵ -catenated (phosphazene) (P4-t-Oct) (42.7*, E) and the like.

As the base catalyst used in the production method according to this embodiment, a base selected from a phosphazene compound, a bicyclic amine compound, a guanidine compound, or an amidine compound is preferably used.
Specific examples of such compounds include the above-mentioned compounds or other compounds whose conjugate acids have a pKa in the range of 8 to 50. For example, examples of phosphazene compounds include P2-t-Bu, P4-t-Bu, BTPP, BEMP, etc., examples of bicyclic amine compounds include ABCO, DABCO, etc., examples of guanidine compounds include MTBD, etc., and examples of amidine compounds include DBU, DBN, etc.
In terms of catalytic activity, among the above compounds, phosphazene compounds, bicyclic amine compounds, and guanidine compounds are more preferred, and phosphazene compounds and bicyclic amine compounds are even more preferred.

Further, examples of the base catalyst used in the production method according to this embodiment include organic polymer-based solid compounds or inorganic solid compounds having, as a substituent or constituent unit, a group derived from a compound whose conjugated acid has a pKa in the range of 8 to 50, a phosphazene compound, a bicyclic amine compound, a guanidine compound, or an amidine compound. These solid compounds may be those produced according to known production methods, or may be various commercially available products.
Since these solid compounds are insoluble in common solvents, they can be easily separated and recovered from the reaction solution by methods such as centrifugation and filtration.
Specific examples of the solid compound include polyacrylic acid derivatives such as polystyrene gel (a copolymer of styrene and divinylbenzene), polyacrylic acid esters, and polyacrylic acid amides having groups derived from trimethylamine, diethylmethylamine, diisopropylmethylamine, methylpiperidine, DBU, MTBD, BEMP, P2-t-Bu, or the like; silica gel; and zeolite.

Specific examples of commercially available organic polymer solid compounds having groups derived from trimethylamine, diethylmethylamine, diisopropylmethylamine, DBU, MTBD, BEMP, P2-t-Bu, etc. include compounds under product numbers 39205, 31866, 538736, 595128, 358754, 536490, and 71477, all of which are commercially available from Merck.

In the manufacturing method according to this embodiment, among organic polymer-based solid compounds, those having groups derived from BEMP, P2-t-Bu, trimethylamine, diisopropylmethylamine, DBU, MTBD, etc. are preferred, and those having groups derived from phosphazene compounds such as BEMP and P2-t-Bu are more preferred.

Furthermore, an inorganic solid compound may be used in which an inorganic compound such as silica or alumina is supported with a compound having a conjugate acid pKa in the range of 8 to 50, a phosphazene compound, a bicyclic amine compound, a guanidine compound, or an amidine compound.
Furthermore, a combination of organic polymer-based solid compounds and inorganic solid compounds can be used, and these solid compounds can also be used in combination with the basic compound.

The amount of base catalyst relative to the raw material can be determined as desired, but the molar or weight ratio relative to the raw material acyloxysilane is usually about 0.001 to 50, preferably about 0.001 to 20, and more preferably about 0.001 to 10.

The decarboxylation reaction in this embodiment can be carried out in a liquid or gas phase state depending on the reaction temperature or pressure. The reaction can be carried out in various conventional reactor configurations, such as a batch type or a flow type.
The reaction temperature is usually 10°C or higher, preferably 10°C to 600°C, more preferably 10°C to 400°C, and further preferably 50°C to 300°C.
Furthermore, the reaction pressure is usually from 0.01 to 30 atm, preferably from 0.01 to 10 atm, and more preferably from 0.01 to 5 atm.
The reaction time depends on the amount of the raw material, the amount of the catalyst, the reaction temperature, the form of the reaction apparatus, etc., but in consideration of productivity and efficiency, it is usually about 1 minute to 24 hours, preferably 1 minute to 20 hours, and more preferably about 1 minute to 16 hours.

When the reaction is carried out in a liquid phase system, it can be carried out with or without a solvent. When a solvent is used, it is possible to use hydrocarbons such as decalin (decahydronaphthalene) and decane, halogenated hydrocarbons such as chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,3-trichlorobenzene, and 1,2,4-trichlorobenzene, ethers such as anisole, tert-butyl methyl ether, dibutyl ether, and tetrahydrofuran, nitriles such as acetonitrile, benzonitrile, and adiponitrile, amides such as dimethylacetamide and methylacetamide, and various solvents other than those that react with the raw materials or catalyst. A base catalyst (e.g., NMP) that exists as a liquid at the reaction temperature may be used as the solvent. Two or more solvents may also be mixed and used.
When the reaction product is analyzed by nuclear magnetic resonance spectroscopy, a deuterated compound such as deuterated acetonitrile, deuterated benzene, deuterated chloroform, deuterated formamide, or deuterated tetrahydrofuran can be used as the reaction solvent.
Furthermore, when the reaction is carried out in a gas phase, the reaction can be carried out by mixing an inert gas such as nitrogen.

The decarboxylation reaction in this embodiment can also be carried out under microwave irradiation. In this reaction system, the dielectric loss coefficients of the raw materials, such as acyloxysilane and silanol, are relatively large and efficiently absorb microwaves, so that the raw materials, catalysts, etc. are activated under microwave irradiation, allowing the reaction to be carried out more efficiently.

In microwave irradiation reactions, various commercially available devices equipped with contact or non-contact temperature sensors can be used. In addition, the microwave irradiation output, the type of cavity (multi-mode, single mode), the irradiation form (continuous, intermittent), etc. can be determined arbitrarily depending on the scale and type of reaction. The microwave frequency is usually 0.3 GHz to 30 GHz. Among these, the IMS frequency band allocated for use in the industrial, scientific, or medical fields is preferable, and even more preferable among these are the 2.45 GHz band, 5.8 GHz band, etc.

In addition, in microwave irradiation reactions, a heating material (susceptor) that absorbs microwaves and generates heat can be added to the reaction system in order to heat the reaction system more efficiently. As the type of heating material, various types of materials known in the art, such as activated carbon, graphite, silicon carbide, and titanium carbide, can be used. In addition, a molded catalyst can be used that is made by mixing the catalyst and heating material powder described above and calcining the mixture using an appropriate binder such as sepiolite or hormite.

The decarboxylation reaction in this embodiment proceeds even in a closed reaction apparatus. However, the reaction can be made more efficient by using an open or reduced pressure reaction apparatus and continuously removing the co-product _CO2 or reaction products from the reaction system.

In the production method of this embodiment, when the above-mentioned solid compound is used as the base catalyst, the base catalyst can be easily separated and recovered after the decarboxylation reaction step by a method such as filtration or centrifugation.
Furthermore, the carbosilane produced can be easily purified by means commonly used in organic chemistry, such as distillation, recrystallization, column chromatography, and the like.

The carbosilane produced by the production method according to this embodiment can be used as a precision synthesis reagent, intermediate, or the like for producing various functional chemicals or various functional materials, such as medicines, agricultural chemicals, optical materials, and electronic materials.
Furthermore, when the carbosilane still has an acyloxy group remaining therein, the acyloxy group has high reactivity, and therefore the carbosilane can also be used as a surface treatment agent for solid materials, etc.
Surface treatment using carbosilanes having acyloxy groups has high reaction efficiency with solid surfaces, making it possible to rapidly perform surface treatment on solid materials such as glass under mild conditions, and the hydrophilicity or hydrophobicity of the solid material surface can be easily controlled depending on the type of carbosilane used.
When a carbosilane having an acyloxy group is used as a surface treatment agent, it can be diluted with an organic solvent that does not react with carbosilane, such as toluene, hexane, or acetone, if necessary.
The surface treatment of the solid material can be carried out by various conventional methods such as a dipping method, a casting method, a spin coating method, a spray coating method, or the like.

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
The main analytical instruments used in the following examples are as follows:
Nuclear magnetic resonance spectroscopy (hereinafter sometimes referred to as NMR): Bruker AVANCE III HD 600MHz (with cryoprobe)
Gas chromatograph analysis (hereinafter sometimes referred to as GC): Shimadzu Corporation GC-2014
Gas chromatograph mass spectrometry (hereinafter sometimes referred to as GC-MS): Shimadzu Corporation GCMS-QP2010Plus

Example 1
[pre-process]
To prepare acyloxysilane, 0.8 mmol of pentafluorobenzoic acid (C ₆ F ₅ CO ₂ H) and 0.8 mL of anisole were stirred in a reaction vessel, while 0.8 mmol of chlorotrimethylsilane (Me ₃ SiCl) and 1.6 mmol of triethylamine were added in sequence at room temperature, and the mixture was stirred for about 30 minutes at room temperature. The salt was separated by centrifugation, and the supernatant and the washings obtained by washing the salt with 0.8 mL of anisole were combined and analyzed by NMR (nuclear magnetic resonance spectrometry) and GC-MS (gas chromatography mass spectrometry). As a result, it was found that 0.72 mmol (yield 90%) of the acyloxysilane trimethyl(pentafluorophenylcarbonyloxy)silane ((C ₆ F ₅ CO ₂ )SiMe ₃ ) was produced (see Table 1-1).
[Decarboxylation reaction process]
0.015 mmol of P2-t-Bu was added to the anisole solution of acyloxysilane obtained in the previous step (about 0.65 mL of anisole solution containing about 0.3 mmol of acyloxysilane), and the mixture was heated at 100° C. for 20 minutes. The reaction solution was analyzed by NMR and GC-MS, and it was found that the conversion rate of acyloxysilane was 92%, and about 0.265 mmol of trimethyl(pentafluorophenyl)silane ((C ₆ F ₅ )SiMe ₃ ) of carbosilane was produced (yield of 96% based on the converted acyloxysilane) (see Table 2-1).
The NMR and GC-MS measurement results of the acyloxysilane obtained in the previous step and the carbosilane obtained in the decarboxylation reaction step are shown in Table 3-1.

The notes in Tables 1-1 and 1-2 are as follows:
1) Type of raw silane
a: Alkoxysilane
b: Allylsilane
c: Chlorosilane
2) _ClSiMe3 : Chlorotrimethylsilane
(EtO) _SiMe3 : Ethoxytrimethylsilane
( _CH2 = _CHCH2 ) _SiMe3 : Allyltrimethylsilane
_ClSiMe2Ph : Chlorodimethylphenylsilane
_ClSiMe2 (CH= _CH2 ): Chlorodimethylvinylsilane
_ClSiMe2 [( _CH2 ) _3CN ]: Chloro(3-cyanopropyl)dimethylsilane
(EtO) _{2SiMe2 :} Diethoxydimethylsilane
_Cl2SiMe2 : _{Dichlorodimethylsilane
ClSiMe2SiMe2Cl} : 1,2-dichloro-1,1,2,2- _{tetramethyldisilane
ClSiMe2OSiMe2Cl} : 1,3-dichloro-1,1,3,3- _{tetramethyldisiloxane} .
3) _{C6F5CO2H : Pentafluorobenzoic} acid
(C ₆ F ₅ CO) ₂ O: Pentafluorobenzoic anhydride
2,3,5,6- _F4C6HCO2H : 2,3,5,6 _{- tetrafluorobenzoic} acid
_2,4,6 - _F3C6H2CO2H : 2,4,6 _{- trifluorobenzoic} acid
_2,6 - _F2C6H3CO2H : 2,6 _{- difluorobenzoic} acid
_2,6 - _Cl2C6H3CO2H : 2,6 _{- dichlorobenzoic} acid
2-( _O2N ) _C6F4CO2H : 3,4,5,6 _{- tetrafluoro} -2-nitrobenzoic acid
2-( _O2N ) _{C6H4CO2H :} 2- _nitrobenzoic acid
_{CF3CF2CO2H : Pentafluoropropionic} acid
(CCl ₃ CO) ₂ O: Trichloroacetic anhydride
1,3- _C6F4 ( _CO2H ) ₂ : _{Tetrafluoroisophthalic} acid
1,4- _C6F4 ( _CO2H ) ₂ : _{Tetrafluoroterephthalic} acid
(PhC≡C) _CO2H : 3-phenylpropiolic acid
4) _Et3N : Triethylamine
NMP: N-methylpyrrolidine
Fe( _ClO4 ) _3.6H2O : Iron(III) _perchlorate hexahydrate
CBV780: USY zeolite CBV780 (manufactured by Zeolist)
5) PhOMe: Anisole
DCB: o-dichlorobenzene When the chlorosilane in b was used as the raw silane and Et ₃ N was used as the reaction accelerator, the salt produced in the reaction was separated by centrifugation, washed with a solvent, and the washing solution was combined with the reaction solution (supernatant solution) to prepare an acyloxysilane solution. The number in square brackets for the amount of solvent is the amount of solvent including the washing solution.
6) ( _C6F5CO2 ) _SiMe3 : _Trimethyl ( _{pentafluorophenylcarbonyloxy} )silane
(2,3,5,6- _F4C6HCO2 ) _SiMe3 : Trimethyl( _{2,3,5,6 -} tetrafluorophenylcarbonyloxy)silane
(2,4,6- _F3C6H2CO2 ) _SiMe3 : Trimethyl( _{2,4,6 - trifluorophenylcarbonyloxy} )silane
(2,6- _{F2C6H3CO2 ) SiMe3} : Trimethyl(2,6 _{- difluorophenylcarbonyloxy} )silane
(2,6 _{- Cl2C6H3CO2 ) SiMe3} : Trimethyl(2,6 _- dichlorophenylcarbonyloxy)silane
[2-( _O2N ) _C6F4CO2 ] _SiMe3 : Trimethyl( _3,4,5,6 -tetrafluoro-2 _- nitrophenylcarbonyloxy)silane
[ _2- ( _O2N ) _C6H4CO2 ] _SiMe3 : Trimethyl(2-nitrophenylcarbonyloxy) _silane
(C ₆ F ₅ CO ₂ )SiMe ₂ Ph: Dimethylphenyl(pentafluorophenylcarbonyloxy)silane
( _C6F5CO2 ) _SiMe2 ( _{CH = CH2} ): dimethyl(pentafluorophenylcarbonyloxy)(vinyl)silane
( _C6F5CO2 ) _SiMe2 [( _CH2 ) _3CN ]: ₍ 3 _- cyanopropyl)dimethyl(pentafluorophenylcarbonyloxy)silane
( _{CF3CF2CO2 ) SiMe3} : Trimethyl( _{pentafluoropropionyloxy} )silane
(CCl ₃ CO ₂ )SiMe ₃ : Trimethyl(trichloroacetyloxy)silane
( _CCl3CO2 ) _SiMe2 (OEt): ₍ ethoxy)dimethyl(trichloroacetyloxy)silane
1,3- _C6F4 ( _CO2SiMe3 ) ₂ : 2,4,5,6 _- tetrafluoro-1,3 _- bis(trimethylsiloxycarbonyl)benzene
1,4- _C6F4 ( _CO2SiMe3 ) ₂ : 2,3,5,6 _- tetrafluoro-1,4 _- bis(trimethylsiloxycarbonyl)benzene
( _C6F5CO2 ) _2SiMe2 : _Dimethylbis ( _{pentafluorophenylcarbonyloxy} ) _silane
( _C6F5CO2 ) _SiMe2SiMe2 ( _OCOC6F5 ): _{1,1,2,2 -} tetramethyl- _{1,2 -} bis(pentafluorophenylcarbonyloxy)disilane
( _C6F5CO2 ) _SiMe2OSiMe2 ( _OCOC6F5 ): 1,1,3,3 _- tetramethyl _{- 1,3 -} bis(pentafluorophenylcarbonyloxy)disiloxane
(PhC≡C)CO ₂ SiMe ₃ : Trimethyl(phenylethynylcarbonyloxy)silane
7) Yield by NMR (yield of acyloxysilane product relative to carboxylic acid derivative or starting silane)

The notes in Tables 2-1 to 2-5 are as follows:
1) (C ₆ F ₅ CO ₂ )SiMe ₃ : Trimethyl(pentafluorophenylcarbonyloxy)silane, ΔU
= 10.10 kcal/mol
(2,3,5,6-F ₄ C ₆ HCO ₂ )SiMe ₃ : Trimethyl(2,3,5,6-tetrafluorophenylcarbonyloxy)silane, ΔU = 10.34 kcal/mol
(2,4,6- _F3C6H2CO2 ) _SiMe3 : Trimethyl( _{2,4,6 - trifluorophenylcarbonyloxy} )silane, ΔU = 11.44 kcal/mol
(2,6- _F2C6H3CO2 ) _SiMe3 : Trimethyl(2,6 _- difluorophenylcarbonyloxy)silane, _ΔU = 11.66 kcal/ _mol
(2,6-Cl ₂ C ₆ H ₃ CO ₂ )SiMe ₃ : Trimethyl(2,6-dichlorophenylcarbonyloxy)silane, ΔU = 18.50 kcal/mol
[2-( _O2N ) _C6F4CO2 ] _SiMe3 : Trimethyl(3,4,5,6 _- tetrafluoro-2 _- nitrophenylcarbonyloxy)silane, ΔU = 11.64 kcal/mol
[2-(O ₂ N)C ₆ H ₄ CO ₂ ]SiMe ₃ : Trimethyl(2-nitrophenylcarbonyloxy)silane, ΔU = 13.86 kcal/mol
(C ₆ F ₅ CO ₂ )SiMe ₂ Ph: dimethylphenyl(pentafluorophenylcarbonyloxy)silane, ΔU = 10.10 kcal/mol
(C ₆ F ₅ CO ₂ )SiMe ₂ (CH═CH ₂ ): dimethyl(pentafluorophenylcarbonyloxy)(vinyl)silane, ΔU = 8.99 kcal/mol
( _C6F5CO2 ) _SiMe2 [( _CH2 ) _3CN ]: ₍ 3 _- cyanopropyl)dimethyl(pentafluorophenylcarbonyloxy)silane, ΔU = 10.01 kcal/mol
(CF ₃ CO ₂ )SiMe ₃ : Trimethyl(trifluoroacetyloxy)silane, ΔU = 13.56 kcal/mol
(CF ₃ CF ₂ CO ₂ )SiMe ₃ : Trimethyl(pentafluoropropionyloxy)silane, ΔU = 13.19 kcal/mol
(CCl ₃ CO ₂ )SiMe ₃ : Trimethyl(trichloroacetyloxy)silane, ΔU = 9.00 kcal/mol
( _CCl3CO2 ) _SiMe2 (OEt): ₍ ethoxy)dimethyl(trichloroacetyloxy)silane, ΔU = 12.38 kcal/mol
1,3-C ₆ F ₄ (CO ₂ SiMe ₃ ) ₂ : 2,4,5,6-tetrafluoro-1,3-bis(trimethylsiloxycarbonyl)benzene, ΔU = 10.52 kcal/mol (1st acyloxy group decarboxylation), 11.73 kcal/mol (2nd acyloxy group decarboxylation)
1,4-C ₆ F ₄ (CO ₂ SiMe ₃ ) ₂ : 2,3,5,6-tetrafluoro-1,4-bis(trimethylsiloxycarbonyl)benzene, ΔU = 9.94 kcal/mol (first acyloxy group decarboxylation), 10.69 kcal/mol (second acyloxy group decarboxylation)
(C ₆ F ₅ CO ₂ ) ₂ SiMe ₂ : dimethylbis(pentafluorophenylcarbonyloxy)silane, ΔU = 8.73 kcal/mol (1st acyloxy group decarboxylation), 9.26 kcal/mol (2nd acyloxy group decarboxylation)
(C ₆ F ₅ CO ₂ )SiMe ₂ SiMe ₂ (OCOC ₆ F ₅ ): 1,1,2,2-tetramethyl-1,2-bis(pentafluorophenylcarbonyloxy)disilane, ΔU = 7.01 kcal/mol (1st acyloxy group decarboxylation), 9.82 kcal/mol (2nd acyloxy group decarboxylation)
(C ₆ F ₅ CO ₂ )SiMe ₂ OSiMe ₂ (OCOC ₆ F ₅ ): 1,1,3,3-tetramethyl-1,3-bis(pentafluorophenylcarbonyloxy)disiloxane, ΔU = 10.16 kcal/mol (1st acyloxy group decarboxylation), 11.66 kcal/mol (2nd acyloxy group decarboxylation)
(PhC≡C)CO ₂ SiMe ₃ : Trimethyl(phenylethynylcarbonyloxy)silane, ΔU = 6.76 kcal/mol
In Examples 1 to 29 and 36 to 61, the pre-step of producing acyloxysilane and the decarboxylation step of producing carbosilane from acyloxysilane were carried out in a continuous one-pot process.
2) The numbers in square brackets are the examples of the previous process in Table 1. "-" indicates that a commercially available acyloxysilane was used.
3) The number in parentheses is the number of moles of acyloxysilane taking into account the yield in the previous step. If no previous step is used and a commercially available acyloxysilane is used, the number of moles is that number.
4) P2-t-Bu: 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ⁵ ,4λ ⁵ -catenated (phosphazene)
BEMP: 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine
BTPP: tert-butylimino-tri(pyrrolidino)phosphorane
ABCO: 1-Azabicyclo[2.2.2]octane
DABCO: 1,4-diazabicyclo[2.2.2]octane
NMP: N-methylpyrrolidine
P4-t-Bu: 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ ⁵ ,4λ ⁵ -catenadi(phosphazene)
TMEDA: N,N,N',N'-Tetramethylethylenediamine
TMPDA: N,N,N',N'-tetramethyl-1,3-propanediamine
BEMP-Pol: Polymer containing BEMP units (Merck, product number 536490)
ⁱ Pr ₂ N-Pol: Diisopropylamino group-containing polymer (Merck, product number 538736)
MTBD-Pol: Polymer containing MTBD units (Merck, product number 358754)
DBU-Pol: DBU unit-containing polymer (Merck, product number 595128)
KF: Potassium fluoride. The polymer compounds used were dried at 80° C. under reduced pressure.
5) The number of moles if the catalyst is a small molecule. If the catalyst is a polymer, the number of moles of basic units.
6) PhOMe: Anisole
DCB: o-dichlorobenzene
NC( _CH2 ) _4CN : Adiponitrile
PhCN: Benzonitrile
THF: tetrahydrofuran.
7) Conversion rate of acyloxysilane by NMR.
8) ( _C6F5 ) _SiMe3 : Trimethyl( _{pentafluorophenyl} )silane
( _C6F4H ) _SiMe3 : Trimethyl( _{tetrafluorophenyl} )silane
( _{C6F3H2 ) SiMe3} : Trimethyl( _{trifluorophenyl} )silane
( _{C6F2H3 ) SiMe3} : Trimethyl( _{difluorophenyl} )silane
( _{C6Cl2H3 ) SiMe3} : Trimethyl( _{dichlorophenyl} )silane
[2-( _O2N ) _C6F4 ] _SiMe3 : Trimethyl(tetrafluoronitrophenyl) _silane
[ _C6H4 ( _NO2 )] _SiMe3 : _Trimethyl (nitrophenyl)silane
( _C6F5 ) _SiMe2Ph : _{Dimethylphenyl} (pentafluorophenyl)silane
( _C6F5 ) _SiMe2 (CH _{= CH2} ): dimethyl(pentafluorophenyl)(vinyl)silane
( _C6F5 ) _SiMe2 [( _CH2 ) _3CN ]: (3 _- cyanopropyl)dimethyl(pentafluorophenyl)silane
( _CF3 ) _SiMe3 : Trimethyl(trifluoromethyl)silane
( _CF3CF2 ) _SiMe3 : Trimethyl( _{pentafluoroethyl} )silane
(CCl ₃ )SiMe ₃ : Trimethyl(trichloromethyl)silane
(CCl ₃ )SiMe ₂ (OEt): (ethoxy)dimethyl(trichloromethyl)silane
1-( _Me3Si )-3-( _Me3SiOCO ) _C6F4 : 2,4,5,6- _tetrafluoro -1-trimethylsilyl-3-trimethylsiloxycarbonylbenzene
1,3-(Me ₃ Si) ₂ C ₆ F ₄ : 2,4,5,6-tetrafluoro-1,3-bis(trimethylsilyl)benzene
1-( _Me3Si )-4-( _Me3SiOCO ) _C6F4 : 2,3,5,6- _tetrafluoro -1-trimethylsilyl-4-trimethylsiloxycarbonylbenzene
1,4-(Me ₃ Si) ₂ C ₆ F ₄ : 2,3,5,6-tetrafluoro-1,4-bis(trimethylsilyl)benzene
( _C6F5 ) _2SiMe2 : _Dimethylbis (pentafluorophenyl) _silane
( _C6F5 ) _SiMe2SiMe2 ( _OCOC6F5 ): 1,1,2,2 _- tetramethyl-1 _- pentafluorophenyl _- 2-pentafluorophenylcarbonyloxydisilane
( _C6F5 ) _SiMe2SiMe2 ( _C6F5 ): 1,1,2,2 _- tetramethyl-1,2 _- bis( _{pentafluorophenyl} )disilane
( _C6F5 ) _SiMe2OSiMe2 ( _OCOC6F5 ): 1,1,3,3 _- tetramethyl-1 _- pentafluorophenyl _- 3-pentafluorophenylcarbonyloxydisiloxane
( _C6F5 ) _SiMe2OSiMe2 ( _C6F5 ): 1,1,3,3 _- tetramethyl-1,3 _- bis( _{pentafluorophenyl} )disiloxane
(PhC≡C) _SiMe3 : Trimethyl(phenylethynyl)silane
9) Yield by NMR (yield of carbosilane product relative to acyloxysilane converted).
10) Three isomers ((C ₆ F ₄ H)SiMe ₃ (P1) to (P3)) were produced, differing in the position of the fluorine atom on the phenyl group. The yields of (P1) to (P3) are shown in parentheses. (C ₆ F ₄ H)SiMe ₃ (P1) is thought to be trimethyl(2,3,5,6-tetrafluorophenyl)silane.
11) Six isomers ((C ₆ F ₃ H ₂ )SiMe ₃ (P1) to (P6)) were produced, differing in the position of the fluorine atom on the phenyl group. The yields of (P1) to (P6) are shown in parentheses. (C ₆ F ₃ H ₂ )SiMe ₃ (P1) is thought to be trimethyl(2,4,6-trifluorophenyl)silane.
12) Five isomers ((C ₆ F ₂ H ₄ )SiMe ₃ (P1) to (P5)) were produced, differing in the position of the fluorine atom on the phenyl group. The yields of (P1) to (P5) are shown in parentheses. (C ₆ F ₂ H ₄ )SiMe ₃ (P1) is thought to be trimethyl(2,6-difluorophenyl)silane.
13) Four isomers ((C ₆ Cl ₂ H ₄ )SiMe ₃ (P1) to (P4)) were produced, differing in the position of the chlorine atom on the phenyl group. The yields of (P1) to (P4) are shown in parentheses. (C ₆ Cl ₂ H ₄ )SiMe ₃ (P1) is thought to be trimethyl(2,6-dichlorophenyl)silane.
14) Two isomers ([C ₆ H ₄ (NO ₂ )]SiMe ₃ (P1) to (P2)) were produced, differing in the position of the nitro group on the phenyl group. The yields of (P1) and (P2) are shown in parentheses. [C ₆ H ₄ (NO ₂ )]SiMe ₃ (P1) is thought to be trimethyl(2-nitrophenyl)silane.
15) Of the two acyloxy groups, one compound was decarboxylated and the other compound was decarboxylated. The yields of the compound with one decarboxylated and the compound with two decarboxylated are shown in parentheses in that order.

The notes in Tables 3-1 to 3-3 are as follows:
1) The names of each compound are listed in footnote 6 of Tables 1-1 and 1-2, or footnotes 1 and 8 of Tables 2-1 to 2-5.
2) ^29Si NMR chemical shift values. _C6D6 was used as the NMR solvent. Cr( _acac ) ₃ (chromium(III) acetylacetonate) was added as a relaxation agent.
3) GC-MS: Gas chromatograph mass spectrometer, EI method: Electron impact ionization method (70 eV).
4) When a soluble phosphazene compound was used as the base catalyst for decarboxylation, silica gel was added to the reaction solution to adsorb and remove the phosphazene compound, and then the reaction solution was subjected to GC-MS measurement.
5) _CDCl3 was used as the NMR solvent.

(Examples 2 to 62)
The reaction and analysis were carried out in the same manner as in Example 1, but the reaction conditions (raw materials, type of base, solvent, temperature, time, etc.) were changed, and the product yields were measured by NMR. The results are shown in Tables 1-1 and 1-2 for the pre-process and in Tables 2-1 to 2-5 for the decarboxylation reaction process. The NMR and GC-MS measurement results for those products are shown in Tables 3-1 to 3-3.

In the method for producing carbosilane of the present invention, the decarboxylation reaction from acyloxysilane proceeds efficiently by using a specific base catalyst.
For example, in the decarboxylation reaction of (C ₆ F ₅ CO ₂ )SiMe ₃ , when P2-t-Bu was used as the base catalyst, the conversion rate of acyloxysilane was 92% and the yield of carbosilane was 96% based on the converted acyloxysilane in anisole at 100° C. for 20 minutes, as shown in Example 1. Even under conditions of 80° C. for 20 minutes, the conversion rate was 70% and the yield was 96% based on the converted acyloxysilane, as shown in Example 2.
On the other hand, when KF, which was known to be an effective catalyst for the decarboxylation reaction of acyloxysilane, was used, as shown in Comparative Example 1, under conditions of 100°C and 20 minutes, the conversion rate of acyloxysilane was 3%, the yield of carbosilane was 0%, and no progress of the decarboxylation reaction was observed, indicating that P2-t-Bu exhibited superior catalytic activity.
This result indicates that by using the base catalyst of the present invention, the decarboxylation reaction proceeds more efficiently than when a conventional catalyst is used.
Furthermore, by using the base catalyst of the present invention, the reaction proceeds efficiently even in a solvent with low toxicity such as anisole (control concentration: not set), which means that there is no need to use harmful substances such as dimethylformamide (control concentration: 10 ppm) that have been used conventionally, and there is a great merit in terms of safety.

The manufacturing method of the present invention makes it possible to more efficiently and safely produce a variety of carbosilanes that are useful as functional chemicals or functional materials, making the present invention highly valuable and of great industrial significance.

Claims (4)

A method for producing a carbosilane having an Si-R bond, comprising a decarboxylation reaction step of carrying out decarboxylation in the presence of a base catalyst from an acyloxysilane having an Si-OCOR bond (OCO represents an oxycarbonyl group, O-C(=O); R represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom, and some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon group may be substituted with groups that do not participate in the reaction), wherein the method for producing a carbosilane satisfies the following condition (1) or conditions (1) and (2), and may also comprise a pre-step of forming an acyloxysilane:
(1) The base catalyst is a phosphazene compound; a bicyclic amine compound; an amidine compound ; or an organic polymer-based compound or an inorganic compound having a group derived from the phosphazene compound, the bicyclic amine compound, or the amidine compound;
the phosphazene compound is 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ⁵ ,4λ ⁵ -catenadi(phosphazene) (P2-t-Bu), 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylideneamino]-2λ ⁵ ,4λ ⁵ -catenadi(phosphazene) (P4-t-Bu), 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP), or tert-butylimino-tri(pyrrolidino)phosphorane (BTPP);
the bicyclic amine compound is 1-azabicyclo[2.2.2]octane (ABCO) or 1,4-diazabicyclo[2.2.2]octane (DABCO);
The amidine compound is 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) or 1,5-diazabicyclo[4.3.0]-5-nonene (DBN).
(2) R in the Si—OCOR bond is an alkyl group or an aryl group in which some or all of the hydrogen atoms bonded to the carbon atom are substituted with halogen atoms, nitro groups, or cyano groups; or an alkynyl group. The method according to claim 1, wherein the pre-step is any one of the following steps (4) to (6), and the pre-step and the decarboxylation reaction step subsequent to the pre-step are carried out continuously.
(4) A step of forming the acyloxysilane having the Si-OCOR bond by reacting an alkoxysilane having a Si-OR' bond (R' represents a hydrocarbon group having 1 to 3 carbon atoms) with a carboxylic anhydride represented by (RCO) _2O (R is as defined above).
(5) A step of forming the acyloxysilane having the Si-OCOR bond by reacting an allylsilane having a Si-R″ bond (R″ represents an allyl group) with a carboxylic acid represented by RCO ₂ H (R has the same meaning as defined above).
(6) A step of forming the acyloxysilane having a Si-OCOR bond by reacting a chlorosilane having a Si-Cl bond with a carboxylic acid represented by RCO ₂ H (R has the same meaning as defined above). The method according to claim 1 or 2, wherein the base catalyst is the phosphazene compound; the bicyclic amine compound; the amidine compound; or an organic polymer-based compound having a group derived from the phosphazene compound, the bicyclic amine compound, or the amidine compound. The method according to any one of claims 1 to 3, wherein the acyloxysilane having a Si-OCOR bond is an acyloxysilane selected from the following general formulas (IA) to (ID):
^{R1aR2bR3cSi ( OCOR} _{) d ( IA} )
_RCO2 ( ^{SiR4R5 )} _m1OCOR (IB)
_RCO2 ( ^{SiR6R7O )} _m2 (COR)(IC)
₍ ^{R8eR9fR10gSiOCO} ₎ ^hR11 ₍ ^{ID )} _​
(In general formulas (IA) to (ID) , a, b, and c are each independently 0 or 1; d is an integer of 1 to 3; a+b+c+d=4; m1 and m2 are each independently an integer of 2 or greater; R has the same meaning as defined above; R ¹ to R ¹⁰ are each independently a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a halogen atom, and some or all of the hydrogen atoms bonded to carbon atoms of the hydrocarbon group or the alkoxy group may be substituted with groups that do not participate in the reaction; e, f, and g are each independently 0 or 1; e+f+g=3; h is an integer of 2 to 4; R ¹¹ is an h-valent hydrocarbon group having 1 to 20 carbon atoms, and some or all of the hydrogen atoms bonded to carbon atoms of the h-valent hydrocarbon group may be substituted with groups that do not participate in the reaction.)