CA2145255A1 - Process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substances - Google Patents
Process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substancesInfo
- Publication number
- CA2145255A1 CA2145255A1 CA002145255A CA2145255A CA2145255A1 CA 2145255 A1 CA2145255 A1 CA 2145255A1 CA 002145255 A CA002145255 A CA 002145255A CA 2145255 A CA2145255 A CA 2145255A CA 2145255 A1 CA2145255 A1 CA 2145255A1
- Authority
- CA
- Canada
- Prior art keywords
- bis
- binaphthyl
- solvent
- reaction
- diphenylphosphinite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic System
- C07F9/02—Phosphorus compounds
- C07F9/28—Phosphorus compounds with one or more P—C bonds
- C07F9/50—Organo-phosphines
- C07F9/53—Organo-phosphine oxides; Organo-phosphine thioxides
- C07F9/5329—Polyphosphine oxides or thioxides
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
- C07C17/10—Preparation of halogenated hydrocarbons by replacement by halogens of hydrogen atoms
- C07C17/14—Preparation of halogenated hydrocarbons by replacement by halogens of hydrogen atoms in the side-chain of aromatic compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Molecular Biology (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Process for preparing2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substances.
The present invention relates to a process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls, by reacting a reaction mixture prepared in a solvent by reaction of 2,2'-dimethyl-1,1'-binaphthyl with a bromina-ting agent and containing 2,2'-bis(bromomethyl)-1,1'-binaphthyl and further brominated binaphthyls, if desired after removal of unreacted brominating agent, reacted brominating agent and/or solvent, with an alkyl diphenyl-phosphinite of the formula RO-P(Ph-(R')n)2, where R is an alkyl radical having from 1 to 5 carbon atoms, Ph is phenyl, R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine and n is 0, 1 or 2, at from 70 to 180°C in the presence or absence of a further solvent.
The invention further relates to compounds of the formula
The present invention relates to a process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls, by reacting a reaction mixture prepared in a solvent by reaction of 2,2'-dimethyl-1,1'-binaphthyl with a bromina-ting agent and containing 2,2'-bis(bromomethyl)-1,1'-binaphthyl and further brominated binaphthyls, if desired after removal of unreacted brominating agent, reacted brominating agent and/or solvent, with an alkyl diphenyl-phosphinite of the formula RO-P(Ph-(R')n)2, where R is an alkyl radical having from 1 to 5 carbon atoms, Ph is phenyl, R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine and n is 0, 1 or 2, at from 70 to 180°C in the presence or absence of a further solvent.
The invention further relates to compounds of the formula
Description
214 S2~
HOECHST AXTIENGESELLSCHAFT HOE 94/F 071 J Dr. Bi/we Description Process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substances.
The present invention relates to an improved process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-bi-naphthyls and also new compounds from this class of substances.
HOECHST AXTIENGESELLSCHAFT HOE 94/F 071 J Dr. Bi/we Description Process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substances.
The present invention relates to an improved process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-bi-naphthyls and also new compounds from this class of substances.
2,2'-Bis(diphenylphosphinylmethyl)-1,1'-binaphthyl (formula I) is an important precursor for the preparation of 2,2'-bis(diphenylphosphinomethyl)-1,1'-binaphthyl (formula II), a bidentate phosphine (phosphane) which is used as a ligand for catalysts, for example in the coupling of haloaromatics catalyzed by metal complexes.
~ ~PPh2 ¢ ~ PPh2 ( I ) ~PPh2 ~pph2 2,2'-Bis(diphenylphosphinylmethyl)-1,1'-binaphthylcanbe prepared in the following manner. The starting material is the correspo~; ng aromatic methyl compound, namely 2,2'-dimethyl-1,1'-binaphthyl, and the methyl group is brominated using N-bromosuccinimide to give 2,2'-bis-(bromomethyl)-1,1'-binaphthyl (formula III). In this reaction, which is described a number of times in the literature and is carried out in the pre~ence of a free-radical former but without the action of light, tetra-chloromethane is generally used as solvent (M. E. Jung et al., Tetrahedron Lett. 29 (1988) 6199; H. J. Bestmann et al., Chem. Ber. 107 (1974) 2926; J.-P. Mazaleyrat, Chem.
Commun. 1985, 317; T. Hayashi et al., J. Am. Chem. Soc.
110 (1988) 8153).
2I~5253~
Owing to the comparatively low boiling point of tetra-chloromethane, namely 76.5C, a reaction at higher temperatures can only be carried out under pre~sure, which requires additional technical complication.
Furthermore, the yield of 2,2'-bis(bromomethyl)-1,1'-binaphthyl achievable by thi~ process i~, at about 60 %, not very high.
The bromination of 2,2'-dimethyl-1,1'-binaphthyl gives, besides the desired product (formula III) essentially two byproducts, presumably 2-bromomethyl-2'-methyl-1,1'-binaphthyl and 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
Although the isolation of 2,2'-bis(bromomethyl)-1,1'-binaphthyl in pure form can be succes~fully carried out by crystallization or by col-~mn chromatography, this is at the cost of, on the one hand, considerable yield losses or, in the ca~e of column chromatography, very high technical complication.
The unpublished European Patent Application EP 93 116 788.6, which goes back, inter alia, to the unpublished German Patent Application P 43 08 562.8, describes the preparation of 2,2'-bi~(bromomethyl)-1,1'-binaphthyl by reaction of 2,2'-dimethyl-1,1'-binaphthyl with N-bromosuccinimide in the presence of benzoyl peroxide, but without the action of light, in chloroben-zene. After the reaction i8 complete, the golvent i8 evaporated, the residue is taken up in ethyl acetate and washed first with 10 % strength Na2SO3 solution then with saturated Na2CO3 ~olution and finally with saturated NaCl solution. After drying and recrystallization, this gives a yield of 65 %. However, thi~ proceRs proves to be complicated (evaporation of the ~olvent, transfer of the residue into another solvent and w~h;ng three times with an aqueous sodium salt ~olution each time), in addition the yield also leave~ something to be de~ired.
_ - 3 -The bromination of 2,2'-dimethyl-1,1'-binaphthyl gen-erally leads to a product mixture which is problematical to handle. It has thus been found that the removal of the solvent, even when carried out under gentle conditions (vacuum), leads to a mixture which is thermally unstable and begins to decompose exothermically above a tempera-ture of only 50C.
It is known from Houben-Weyl, Me~hoAen der organischen Chemie, volume V/4, pages 333 and 334, that aralkyl bromides in the pure state are colorless substances usually having little thermal stability and some of them cannot be distilled without decomposition, even in vacuo.
Naphthylmethyl bromides are generally less ~table then benzyl bromide~.
For this reason, the isolation of the crude product formed in the bromination is encumbered by a considerable hazard potential which, in particular for the large amounts of starting materials or raw materials handled on an industrial scale, poses an unpredictable risk.
~r RO-P(Ph-(R )n)2 ( IV) [~e, To prepare 2,2'-bis(diphenylphosphinylmethyl)-1,1'-bi-naphthyl (formula I), pure 2,2'-bis(bromomethyl)-1,1'-bi-naphthyl, i.e. not a mixture of various b I ;nAted binaphthyls, can be subjected to the Arbusov reaction with methyl diphenylphosphinite (formula IV, where R is CH3 and n is 0) without addition of a solvent. As described in JP 7 939 059 or CA 91,91764 v, the two abovementioned components are heated in a ratio of 1:6.7 for three hours at 130C to give the desired product (formula I). The reaction is, however, problematical, 2~2~5 since, as can be seen from Experiment 4 of JP 7 939 059, an explosive reaction occurs at 87C. The yield achieved i8 only 30 %. The process is not suitable for an indus-trial process, neither with regard to the required process safety nor with regard to the yield.
There is therefore a need to develop a proces~ for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaph-thyls which does not have the abovementioned disadvan-tages, can also be carried out simply and reliably and enables the desired product to be obtained in high yield and purity.
This object i8 achieved by a process for preparing 2,2'-biæ(diphenylphosphinylmethyl)-1,1'-binaphthyl~. It comprises reacting a reaction mixture prepared in a solvent by reaction of 2,2'-dimethyl-1,1'-binaphthyl with a brominating agent and containing 2,2'-bis(bromomethyl)-l,l'-binaphthyl and further brominated binaphthyls, if desired after removal of unreacted brominating agent, reacted brominating agent and/or solvent, with an alkyl diphenylphosphinite of the formula (IV) R0-P(Ph-(R')n)2, where R is an alkyl radical having from 1 to 5, in particular from 1 to 3, carbon atoms, Ph is phenyl, R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine, in particular methyl, CF3 or fluorine, and n is 0, 1 or 2, at from 70 to 180C in the presence or absence of a further solvent.
An advantage of the process of the invention is that in the preparation of the reaction mixture, isolation of the 2,2~-bis(bromomethyl)-1,1'-binaphthyl (formula III) is omitted and in this way a quite complicated separation operation, which owing to the thermal instability of the reaction product formed in the bromination also presents a safety risk, is avoided. Furthermore, with suitable selection of the solvent, the solvent used in the reaction can remain in the reaction mixture. It does not have to be removed from the reaction mixture.
21~52~5 However, it i8 also possible to replace, if required, the solvent originally used in the bromination step by a further solvent and to completely or partially distil off the solvent originally used. In this way, although the solvent originally used is replaced by the further solvent, a quite complicated separation operation (isola-tion of the 2,2'-bis(bromomethyl)-1,1'-binaphthyl) can nevertheless be avoided.
The reaction mixture contains, independently of the method of bromination, the brominated compounds usually formed in a bromination, namely, besides the desired product, essentially pre~umably the two abovementioned brominated byproducts and also the solvent. The reaction mixture generally obtained contains from 60 to 85 mol %, in particular from 65 to 83 mol %, of 2,2'-bis(bromo-methyl)-1,1'-binaphthyl and from 40 to 15 mol %, in particular from 35 to 17 mol %, of further brominated binaphthyls, with the solvent ~till present not being taken into account.
The one byproduct, presumably 2-bromomethyl-2'-methyl-1,1'-binaphthyl, makes up from 1 to 20 mol %, in particu-lar from 3 to 18 mol %, and the other byproduct, presum-ably2-dibromomethyl-2'-bromomethyl-1,1'-binaphthylmakes up from 3 to 20 mol %, in particular from 5 to 17 mol %.
The method of bromination also influences to a certain extent both the amount of the brominated binaphthyls formed and also the ratio in which the two abovementioned byproducts are formed.
~n general, the amount of solvent used is of no great importance. However, a sufficient amount should be used.
In general it i8 sufficient to use 2,2'-dimethyl-1,1~-binapthyl and the solvent in a weight ratio of 1:(3 to 40), in particular 1:(4 to 20), preferably 1:(5 to 15).
Solvents which can be used are generally those which are inert under the reaction conditions of the bromination.
2I~525~
Use can be made of monochlorinated or polychlorinated benzene, a monochlorinated or polychlorinated aliphatic hydrocarbon, an ester of an aliphatic carboxylic acid having from 1 to 6 carbon atoms and an alkyl alcohol having from 1 to 4 carbon atoms or mixtures thereof as solvents. Examples of such solvents are chloroform, dichloromethane, tetrachloromethane, chlorobenzene, ortho-, meta- and para-dichlorobenzene, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate and propyl propionate. Well-suited solvents are chlorobenzene or dichlorobenzene or any mixture of these solvents. Chloro-benzene is particularly useful.
In some cases, esters of the abovementioned type, in particular methyl and ethyl esters of aliphatic carboxy-lic acids having from 1 to 3 carbon atoms, can also be used with good results.
In the preparation of the reaction mixture, the bromina-tion can be carried out under the action of light having a wavelength of from 10-5 to 10-8 m, in particular from 10-6 to 2x10-7. It i~ here usual to allow the reaction of 2,2'-dimethyl-1,1'-binaphthyl to proceed at from -10 to 75C. In many cases, it is found to be sufficient to react 2,2'-dimethyl-1,1'-binaphthyl with the brominating agent at from -5 to 50C, in particular from O to 40C.
The light source used for the bromination can be a conventional W irradiator, for example a daylight lamp, a doped or undoped mercury vapor lamp or low-pressure mercury vapor lamp. On the other hand, 2,2'-dimethyl-1,1'-binaphthyl and the brominating agent can be reacted in the absence of light, but in the presence of a free-radical former at from 25 to 150C, in particular from 40 to 135C.
The bromination can be carried out using a customary brominating agent, for example bromine, 2I I ~S
N-bromosuccinimide, 1,3-dibromo-5,5-dimethylhydantoin, brominated Meldrum's acid.
It has been found to be favorable to react 2,2'-dimethyl-1,1'-binaphthyl with N-bromosuccinimide as brominating agent. 2,2'-Dimethyl-1,1'-binaphthyl and N-bromosuccini-mide are usually used in a molar ratio of 1:(1.5 to 2.5), in particular 1:(1.8 to 2.3), preferably 1:(1.9 to 2.2).
In the course of the bromination, N-bromosuccinimide forms succinimide which, if desired after cooling the solution containing the reaction product, is removed by filtration. A further possibility is to remove the succinimide formed by extraction with water. For this purpo~e, from 10 to 100% by weight of water, based on reaction mixture, are usually used.
A particularly simple and at the same time effective method of removing succinimide is to separate the succi-nimide formed from the reaction mixture in a first step by filtration and in a second step by extraction with water. This uses comparatively little water and accor-dingly also gives little wastewater.
The bromination carried out under the action of lightgives the desired product in a yield of about 80 %. In addition, it usually gives from 1 to 6 % of a brominated substance, pre~umably 2-bL~.o_.cthyl-2'-methyl-1,1'-binaphthyl, and from 7 to 13 % of a further byproduct,presumably 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
The correspon~i ng reaction mixture (A) used in the Arbusov reaction presumably contains, besides small amounts of substances not identified in more detail, the abovementioned bromo compounds dissolved in the solvent, for example in chlorobenzene and/or dichlorobenzene, in particular in chlorobenzene.
In place of the reaction mixture (A) prepared under the 21~525S-action of light, it is also possible to use a reaction mixture (B) which can be obtained, for example, by reaction of 2,2'-dimethyl-1,1'-binaphthyl with N-bromo-succinimide in the presence of a solvent under the action of a free-radical former (free-radical initiator) and by subæequent removal of succinimide, with good results in the Arbusov reaction (reaction with the alkyl diphenyl-phosphinite). Such a reaction mixture (B) can be prepared by reacting 2,2'-dimethyl-1,1'-binaphthyl with N-bromo-succinimide, for example in a molar ratio of 1:(1.5 to2.5), in particular 1:(1.8 to 2.3), preferably 1:(1.9 to 2.2), at elevated temperature, usually at temperatures of from 25 to 150C, in particular from 40 to 135C, under the action of a free-radical initiator in chlorobenzene and/or dichlorobenzene, removing ~uccinimide formed, but without removing the chlorobenzene and/or dichlorobenzene used as solvent.
Suitable free-radical initiators are the customary free-radical formers, for example organic peroxides, hydro-peroxides, azobisisobutyronitrile.
The bromination carried out under the action of the free-radical initiator gives the desired product in a yield of from about 63 to 67 %. In addition, it generally gives from 10 to 20 % of a brominated product, presumably 2-bromomethyl-2'-methyl-1,1'-binaphthyl, and from 8 to 15 % of a further byproduct, presumably 2-dibromomethyl-2-bromomethyl-1,1'-binaphthyl. The reaction mixture (B) used in the Arbusov reaction presumably contains, besides small amounts of substances not identified in more detail, the abovementioned bromo compounds dissolved in chlorobenzene and/or dichlorobenzene, in particular chlorobenzene.
The ~uccinimide formed from the N-bromosuccinimide is separated from the bromination mixture, if desired after cooling, by filtration. Another possibility is to carry out the subsequent removal of succinimide by extraction with water.
21~525~
g A particularly simple and effective variant is to separate succinimide from the bromination mixture in a first step by filtration and in a second step by extraction with water.
Unreacted free-radical formers can be removed, for example, by scrubbing with an aqueous Na2S03 solution.
The abovedescribed procedure gives the reaction mixture (B).
To carry out the Arbusov reaction, the reaction mixture, for example the reaction mixture (A) or the reaction mixture (B), is reacted with an alkyl diphenylphosphinite (formula IV), as already mentioned above, at from 70 to 180C. In many cases, it is sufficient to carry out the reaction at from 100 to 170C, in particular from 120 to 160C. The reaction proceeds according to the following equation:
I ~ l~e, ~ ~ h - ( 11 ) " ) 2 Ito-~(~h-(~ [~ ;(Fh-(R')")~
( I I I ) ( lV) ( 10) The alkyldiphenylphosphinite of the formula (IV) uRed is usually a (Cl-C5)alkyl diphenylphosphinite or a mixture of these esters. Suitable alkyl diphenylphosphinites are, without claiming completene~, methyl diphenylphos-phinite, ethyl diphenylphosphinite, isopropyl diphenyl-phosphinite, n-propyl diphenylphosphinite, ethyl bis(3-fluorophenyl)phosphinite, ethyl bis(4-fluorophenyl)-phosphinite, ethyl bis(2-methylphenyl)phosphinite and/or ethyl bis(3-trifluoromethylphenyl)phosphinite.
The alkyl diphenylphosphinite is generally used in a 21 ~5~55 molar ratio of (1.8 to 4):1, in particular (1.9 to 3):1, preferably (2 to 2.5):1, based on the 2,2'-dimethyl-1,1'-binaphthyl. However, in many cases it is possible to use the alkyl diphenylphosphinite (formula IV), based on 2,2'-dimethyl-1,1'-binaphthyl used, in the stoichiometric ratio or in a slight excess.
Before the reaction mixture resulting from the bromina-tion stage is used in the subseguent Arbusov reaction (reaction with the alkyl diphenylphosphinite), it is advisable, as mentioned above, in many cases to remove the unreacted brominating agent and/or the reacted brominating agent and/or the solvent used in the bromina-tion stage.
Unreacted brominating agent, for example bromine, can be removed by vaporization, reacted brominating agent, for example succinimide, can be removed by filtration and extraction. The solvent used in the bromination stage is replaced by a further solvent which has a boiling point higher than that of the solvent originally used. The further solvent is added prior to the reaction or during the reaction or after the reaction of the reaction mixture with the alkyl diphenylphosphinite and the solvent originally used is subsequently distilled off.
This removal of the original solvent can be carried out prior to the Arbusov reaction or even during the Arbusov reaction or after the Arbusov reaction. If a solvent which is inert to the Arbusov reaction is used as ori-ginal solvent, it can be removed during the Arbusov reaction or the removal can even be omitted. Such sol-vents are, for example, chlorobenzene, dichlorobenzeneand mixtures thereof; when they are used a removal i~ not absolutely necessary.
Solvents which are not inert to the Arbusov reaction have to be removed prior to carrying out the Arbusov reaction.
Such solvents are, for example, monochlorinated or polychlorinated aliphatic hydrocarbons.
Suitable further solvents are generally solvents which have a boiling point higher than that of the solvent originally used and which are inert under the conditions of the Arbusov reaction. These include aromatic hydrocar-bons, for example toluene, o-xylene, m-xylene, p-xylene, mixtures of these xylenes, ethylbenzene and/or me~itylene and high-boiling aliphatic hydrocarbons, for example petroleum ether having a boiling point ~ 100C, decalin, ligroin and/or isooctane.
The Arbusov reaction can thus be carried out in the presence or absence of a further solvent.
In some cases it has been found to be advantageous to add the further, nonpolar solvent which has a boiling point higher than that of the solvent originally used during the Arbusov reaction (reaction with the alkyl diphenyl-phosphinite) and to simultaneously distill off the solvent originally used, for example chlorobenzene and/or dichlorobenzene. Suitable solvents for this purpose are, for example, aromatic compounds having boiling points higher than chlorobenzene and/or dichlorobenzene, for example o-xylene, m-xylene, p-xylene, mixtures of these xylenes and/or mesitylene. This allows the yield of 2,2'-bis(diphenylphosphinylmethyl)-l,1'-binaphthylisolatedto be increased somewhat further.
It is surprising that the brominated binaphthyls, for example the brominated byproducts present in both the reaction mixture (A) and in the reaction mixture (B) generally do not interfere in the Arbusov reaction and also do not impair the quality of the desired final product (formula I). Furthermore, it i~ unexpected that the use of a solvent, for example the use of chloroben-zene and/or dichlorobenzene, in the Arbusov reactionleads to a significant increaRe in yield. While the process of JP 7 939 059 gives a yield of only 30 %, the process of the invention gives a yield of from 90 to 95 %
of desired product, in each case based on 2,2'-bis(bromo-methyl)-1,1'-binaphthyl. In addition, the danger of the reaction occurring explosively is avoided.
21~5~5~
To carry out the Arbusov reaction, the reaction mixture, for example reaction mixture (A) or the reaction (B) or mixtures of the two reaction mixtures, is usually initially charged and heated to the prescribed tem-perature. It is advantageous to select a temperaturebelow the boiling point of the solvent used. After reaching the reaction temperature, the alkyl diphenyl-phosphinite is 610wly added dropwise to the initially charged reaction solution. As the reaction proceeds, it results in the formation of alkyl bromide which is continuously distilled from the reaction product. If desired, the mixture can also be boiled under reflux for some time after the end of the addition of the alkyl diphenylphosphinite, 80 as to complete the reaction.
If it is intended that the solvent originally used be removed during the Arbusov reaction, a temperature above the boiling point of the original solvent but below that of the further solvent added is selected. In this way, both the alkyl bromide and also the solvent originally used distills off.
The process of the invention makes it possible to obtain the new compounds of the formula (Ia) ~R') (~/ )2 )2 where R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine, in particular methyl, CF3 or fluorine, and n i8 1 or 2, in a sur-prisingly simple manner by reaction of 2,2'-bis(bromo-methyl)-1,1'-binaphthyl of the formula (III) with the corresponding diphenylphosphinic ester of the formula IV.
New compounds in this category which may be mentioned are, in particular, 2,2'-bis[bis(3-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl, 2,2'-bis[bis(4-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl, 2,2'-bis[bis(2-methylphenyl)phosphinylmethyl]-1,1'-binaphthyl and 2,2'-bis[bis(3-trifluoromethylphenyl)phosphinylmethyl]-l,l'-binaphthyl.
The following examples illustrate the invention without limiting it.
Experimental part:
Example 1 Preparation using a reaction mixture A
With exclusion of moisture, 282.4 g (1.0 mol) of 2,2'-dimethyl-l,l'-binaphthyl and 373.8 g (2.1 mol) of N-bromosuccinimide are suspended in 1.7 1 of chloro-benzene in a 4 1 glass flask and are illuminated with a W immersion lamp for 8 hours at from 5 to 10C. The precipitated succinimide is filtered off, the solution is extracted twice with 200 ml of water each time, dried using sodium sulfate and filtered. The filtrate (reaction mixture A) is transferred to a 4 l four-neck flask fitted with stirrer, dropping funnel, reflux condenser and internal thermometer and is heated to 125C. 460.5 g (2.0 mol) of ethyl diphenylphosphinite are then slowly added dropwise, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C.
The solid is filtered off, washed with cold chlorobenzene and dried in vacuo. This gives 512 g (purity: ~ 99 %) of 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyl as colorless crystals having a melting point of from 287 to 21~52~
289C, correspo~;ng to 75 % total yield based on 2,2'-dimethyl-1,1'-binaphthyl used.
Composition according to GC analysis (in mol %) without solvent:
80 % of 2,2'-bis(bLu~.u~.cthyl)-l,l'-binaphthyl 2 % of 2-bromomethyl-2'-methyl-1,1'-binaphthyl 13 % of 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
Example 2 Preparation using a reaction mixture A
With exclusion of moisture, 282.4 g (1.0 mol) of 2,2'-dimethyl-1,1'-binaphthyl and 373.8 g (2.1 mol) of N-bromosuccinimide are suspended in 1.7 1 of chloro-benzene in a 4 1 glass flask and are illuminated with a W immersion lamp for 8 hours at from 5 to 10C. The precipitated succinimide is filtered off, the solution i8 extracted twice with 200 ml of water each time, dried using sodium sulfate and filtered. The filtrate (reaction mixture A) is transferred to a 4 1 four-neck flask fitted with stirrer, dropping funnel, reflux condenser and internal thermometer and i8 heated to 125C. 488.6 g (2.0 mol) of propyl diphenylphosphinite are then slowly added dropwise, with n-propyl bromide distilling off.
After the end of the addition, the mixture is heated under reflux for a further two hours and iæ then cooled to 0C. The solid is filtered off, washed with cold chlorobenzene and dried in vacuo. This gives 502.5 g of 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyl (purity: ~ 99 ~) as colorless crystals having a melting point of from 287 to 289C, correspo~;ng to 73.5 % total yield based on 2,2'-dimethyl-1,1'-binaphthyl used.
Composition according to GC analysis (in mol %) without solvent:
68 % of 2,2'-bis(bromomethyl)-1,1'-binaphthyl 15 % of 2-bromomethyl-2'-methyl-1,1'-binaphthyl 13 % of 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
Example 3 Preparation using a reaction mixture B
With exclusion of moisture, 282.4 g (1.0 mol) of 2,2'-dimethyl-l,l'-binaphthyl, 373.8 g (2.1 mol) of N-bromosuccinimide and 500 mg of benzoyl peroxide are suspended in 1.7 1 of chlorobenzene in a 4 1 glass flaæk and are stirred for 3.5 hours at the boiling point. The precipitated succinimide is filtered off, the solution is extracted twice with 200 ml of water each time and once with 100 ml of Na2S03 solution, dried using sodium sulfate and filtered. The filtrate (reaction mixture B) is transferred to a 4 1 four-neck flask fitted with stirrer, dropping funnel, reflux condenser and internal thermometer and is heated to 125C. 460.5 g (2.0 mol) of ethyl diphenylphosphinite are then slowly added dropwise, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold chlorobenzene and dried in vacuo. This gives 443.8 g (purity: ~ 99 %) of 2,2'-bis-(diphenylphosphinylmethyl)-l,l'-binaphthyl as colorless crystals having a melting point of from 287 to 289C, correspon~;n~ to 65 % total yield based on 2,2'-dimethyl-l,l'-binaphthyl used.
Composition according to GC analysis (in mol %) without solvent:
68 ~ of 2,2'-bi 5 (bromomethyl)-1,1'-binaphthyl 15 % of 2-bromomethyl-2'-methyl-1,1'-binaphthyl 13 % of 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
21 4525~
Example 4 2,2'-Bis[bis(3-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl While stirring under nitrogen, 8.8 g (33 mmol) of ethyl bis(3-fluorophenyl)phosphinite are slowly added dropwise to a solution of 7.27 g (16.6 mmol) of 2,2'-bis(bromo-methyl)-l,l'-binaphthyl in 40 ml of o-xylene, which solution has been heated to 120C, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold o-xylene and dried in vacuo. This gives 11.5 g (91 %) of colorless crystals having a melting point of 280-284C.
31P-NMR: ~ (CDCl3) = 27.3 ppm Example 5 2,2'-Bis[bis(4-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl While stirring under nitrogen, 10.70 g (0.04 mol) of ethyl bis(4-fluorophenyl)phosphinite are added dropwise to a solution of 8.80 g (0.02 mol) of 2,2'-bis(bromo-methyl)-l,l'-binaphthyl in 40 ml of o-xylene, which solution has been heated to 135C. After the end of the addition, the mixture is heated under reflux for a further 1.5 hours. After cooling to room temperature, the precipitated crystals are filtered off with suction and wa~hed with xylene. This give~ 14.1 g (94 %) of colorle~s crystals having a melting point of 211-214C.
31P-NMR: ~ (CDCl3) = 28.2 ppm 21~525-~
Example 6 2,2'-Bis~bis(2-methylphenyl)phosphinylmethyl]-1,1'-bi-naphthyl While stirring under nitrogen, 21.5 g (83 mmol) of ethyl bis(2-methylphenyl)phosphinite are slowly added dropwise to a solution of 18.4 g (42 mmol) of 2,2'-bis(bromo-methyl)-1,1'-binaphthyl in 100 ml of o-xylene, which solution has been heated to 120C, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold o-xylene and dried in vacuo. This gives 25.1 g (81 %) of colorless crystals having a melting point of 231-234C.
31P-NMR: ~ (CDCl3) = 30.5 ppm Example 7 2,2'-Bis[bis(3-trifluoromethylphenyl)phosphinylmethyl]-1,1'-binaphthyl While stirring under nitrogen, 20.1 g (55 mmol) of ethyl bis(3-trifluoromethylphenyl)phosphinite are slowly added dropwise to a solution of 11.0 g (25 mmol) of 2,2'-bis(bromomethyl)-1,1'-binaphthyl in 80 ml of o-xylene, which solution has been heated to 120C, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and i8 then cooled to 0C. The solid i9 filtered off, washed with cold o-xylene and dried in vacuo. This gives 16.1 g (68 %) of colorless crystals.
31P-NMR: ~ (CDCl3) = 27.1 ppm Example 8 (Arbusov in ethyl acetate) While stirring under nitrogen, 88.5 g (385 mmol) of ethyl 21~52~5 diphenylphosphinite are slowly added dropwise to a solution of 77.0 g (I75 mmol) of 2,2'-bis(bromomethyl)-1,1'-binaphthyl in 400 ml of ethyl acetate, which 801u-tion has been heated to 78C, and ethyl bromide is simultaneously distilled off via an 80 cm Vigreux column.
After the end of the addition, the mixture i8 heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold ethyl acetate and dried in vacuo. This gives 85.0 g (71 %) of colorless crystals having a melting point of 287-289C.
~ ~PPh2 ¢ ~ PPh2 ( I ) ~PPh2 ~pph2 2,2'-Bis(diphenylphosphinylmethyl)-1,1'-binaphthylcanbe prepared in the following manner. The starting material is the correspo~; ng aromatic methyl compound, namely 2,2'-dimethyl-1,1'-binaphthyl, and the methyl group is brominated using N-bromosuccinimide to give 2,2'-bis-(bromomethyl)-1,1'-binaphthyl (formula III). In this reaction, which is described a number of times in the literature and is carried out in the pre~ence of a free-radical former but without the action of light, tetra-chloromethane is generally used as solvent (M. E. Jung et al., Tetrahedron Lett. 29 (1988) 6199; H. J. Bestmann et al., Chem. Ber. 107 (1974) 2926; J.-P. Mazaleyrat, Chem.
Commun. 1985, 317; T. Hayashi et al., J. Am. Chem. Soc.
110 (1988) 8153).
2I~5253~
Owing to the comparatively low boiling point of tetra-chloromethane, namely 76.5C, a reaction at higher temperatures can only be carried out under pre~sure, which requires additional technical complication.
Furthermore, the yield of 2,2'-bis(bromomethyl)-1,1'-binaphthyl achievable by thi~ process i~, at about 60 %, not very high.
The bromination of 2,2'-dimethyl-1,1'-binaphthyl gives, besides the desired product (formula III) essentially two byproducts, presumably 2-bromomethyl-2'-methyl-1,1'-binaphthyl and 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
Although the isolation of 2,2'-bis(bromomethyl)-1,1'-binaphthyl in pure form can be succes~fully carried out by crystallization or by col-~mn chromatography, this is at the cost of, on the one hand, considerable yield losses or, in the ca~e of column chromatography, very high technical complication.
The unpublished European Patent Application EP 93 116 788.6, which goes back, inter alia, to the unpublished German Patent Application P 43 08 562.8, describes the preparation of 2,2'-bi~(bromomethyl)-1,1'-binaphthyl by reaction of 2,2'-dimethyl-1,1'-binaphthyl with N-bromosuccinimide in the presence of benzoyl peroxide, but without the action of light, in chloroben-zene. After the reaction i8 complete, the golvent i8 evaporated, the residue is taken up in ethyl acetate and washed first with 10 % strength Na2SO3 solution then with saturated Na2CO3 ~olution and finally with saturated NaCl solution. After drying and recrystallization, this gives a yield of 65 %. However, thi~ proceRs proves to be complicated (evaporation of the ~olvent, transfer of the residue into another solvent and w~h;ng three times with an aqueous sodium salt ~olution each time), in addition the yield also leave~ something to be de~ired.
_ - 3 -The bromination of 2,2'-dimethyl-1,1'-binaphthyl gen-erally leads to a product mixture which is problematical to handle. It has thus been found that the removal of the solvent, even when carried out under gentle conditions (vacuum), leads to a mixture which is thermally unstable and begins to decompose exothermically above a tempera-ture of only 50C.
It is known from Houben-Weyl, Me~hoAen der organischen Chemie, volume V/4, pages 333 and 334, that aralkyl bromides in the pure state are colorless substances usually having little thermal stability and some of them cannot be distilled without decomposition, even in vacuo.
Naphthylmethyl bromides are generally less ~table then benzyl bromide~.
For this reason, the isolation of the crude product formed in the bromination is encumbered by a considerable hazard potential which, in particular for the large amounts of starting materials or raw materials handled on an industrial scale, poses an unpredictable risk.
~r RO-P(Ph-(R )n)2 ( IV) [~e, To prepare 2,2'-bis(diphenylphosphinylmethyl)-1,1'-bi-naphthyl (formula I), pure 2,2'-bis(bromomethyl)-1,1'-bi-naphthyl, i.e. not a mixture of various b I ;nAted binaphthyls, can be subjected to the Arbusov reaction with methyl diphenylphosphinite (formula IV, where R is CH3 and n is 0) without addition of a solvent. As described in JP 7 939 059 or CA 91,91764 v, the two abovementioned components are heated in a ratio of 1:6.7 for three hours at 130C to give the desired product (formula I). The reaction is, however, problematical, 2~2~5 since, as can be seen from Experiment 4 of JP 7 939 059, an explosive reaction occurs at 87C. The yield achieved i8 only 30 %. The process is not suitable for an indus-trial process, neither with regard to the required process safety nor with regard to the yield.
There is therefore a need to develop a proces~ for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaph-thyls which does not have the abovementioned disadvan-tages, can also be carried out simply and reliably and enables the desired product to be obtained in high yield and purity.
This object i8 achieved by a process for preparing 2,2'-biæ(diphenylphosphinylmethyl)-1,1'-binaphthyl~. It comprises reacting a reaction mixture prepared in a solvent by reaction of 2,2'-dimethyl-1,1'-binaphthyl with a brominating agent and containing 2,2'-bis(bromomethyl)-l,l'-binaphthyl and further brominated binaphthyls, if desired after removal of unreacted brominating agent, reacted brominating agent and/or solvent, with an alkyl diphenylphosphinite of the formula (IV) R0-P(Ph-(R')n)2, where R is an alkyl radical having from 1 to 5, in particular from 1 to 3, carbon atoms, Ph is phenyl, R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine, in particular methyl, CF3 or fluorine, and n is 0, 1 or 2, at from 70 to 180C in the presence or absence of a further solvent.
An advantage of the process of the invention is that in the preparation of the reaction mixture, isolation of the 2,2~-bis(bromomethyl)-1,1'-binaphthyl (formula III) is omitted and in this way a quite complicated separation operation, which owing to the thermal instability of the reaction product formed in the bromination also presents a safety risk, is avoided. Furthermore, with suitable selection of the solvent, the solvent used in the reaction can remain in the reaction mixture. It does not have to be removed from the reaction mixture.
21~52~5 However, it i8 also possible to replace, if required, the solvent originally used in the bromination step by a further solvent and to completely or partially distil off the solvent originally used. In this way, although the solvent originally used is replaced by the further solvent, a quite complicated separation operation (isola-tion of the 2,2'-bis(bromomethyl)-1,1'-binaphthyl) can nevertheless be avoided.
The reaction mixture contains, independently of the method of bromination, the brominated compounds usually formed in a bromination, namely, besides the desired product, essentially pre~umably the two abovementioned brominated byproducts and also the solvent. The reaction mixture generally obtained contains from 60 to 85 mol %, in particular from 65 to 83 mol %, of 2,2'-bis(bromo-methyl)-1,1'-binaphthyl and from 40 to 15 mol %, in particular from 35 to 17 mol %, of further brominated binaphthyls, with the solvent ~till present not being taken into account.
The one byproduct, presumably 2-bromomethyl-2'-methyl-1,1'-binaphthyl, makes up from 1 to 20 mol %, in particu-lar from 3 to 18 mol %, and the other byproduct, presum-ably2-dibromomethyl-2'-bromomethyl-1,1'-binaphthylmakes up from 3 to 20 mol %, in particular from 5 to 17 mol %.
The method of bromination also influences to a certain extent both the amount of the brominated binaphthyls formed and also the ratio in which the two abovementioned byproducts are formed.
~n general, the amount of solvent used is of no great importance. However, a sufficient amount should be used.
In general it i8 sufficient to use 2,2'-dimethyl-1,1~-binapthyl and the solvent in a weight ratio of 1:(3 to 40), in particular 1:(4 to 20), preferably 1:(5 to 15).
Solvents which can be used are generally those which are inert under the reaction conditions of the bromination.
2I~525~
Use can be made of monochlorinated or polychlorinated benzene, a monochlorinated or polychlorinated aliphatic hydrocarbon, an ester of an aliphatic carboxylic acid having from 1 to 6 carbon atoms and an alkyl alcohol having from 1 to 4 carbon atoms or mixtures thereof as solvents. Examples of such solvents are chloroform, dichloromethane, tetrachloromethane, chlorobenzene, ortho-, meta- and para-dichlorobenzene, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate and propyl propionate. Well-suited solvents are chlorobenzene or dichlorobenzene or any mixture of these solvents. Chloro-benzene is particularly useful.
In some cases, esters of the abovementioned type, in particular methyl and ethyl esters of aliphatic carboxy-lic acids having from 1 to 3 carbon atoms, can also be used with good results.
In the preparation of the reaction mixture, the bromina-tion can be carried out under the action of light having a wavelength of from 10-5 to 10-8 m, in particular from 10-6 to 2x10-7. It i~ here usual to allow the reaction of 2,2'-dimethyl-1,1'-binaphthyl to proceed at from -10 to 75C. In many cases, it is found to be sufficient to react 2,2'-dimethyl-1,1'-binaphthyl with the brominating agent at from -5 to 50C, in particular from O to 40C.
The light source used for the bromination can be a conventional W irradiator, for example a daylight lamp, a doped or undoped mercury vapor lamp or low-pressure mercury vapor lamp. On the other hand, 2,2'-dimethyl-1,1'-binaphthyl and the brominating agent can be reacted in the absence of light, but in the presence of a free-radical former at from 25 to 150C, in particular from 40 to 135C.
The bromination can be carried out using a customary brominating agent, for example bromine, 2I I ~S
N-bromosuccinimide, 1,3-dibromo-5,5-dimethylhydantoin, brominated Meldrum's acid.
It has been found to be favorable to react 2,2'-dimethyl-1,1'-binaphthyl with N-bromosuccinimide as brominating agent. 2,2'-Dimethyl-1,1'-binaphthyl and N-bromosuccini-mide are usually used in a molar ratio of 1:(1.5 to 2.5), in particular 1:(1.8 to 2.3), preferably 1:(1.9 to 2.2).
In the course of the bromination, N-bromosuccinimide forms succinimide which, if desired after cooling the solution containing the reaction product, is removed by filtration. A further possibility is to remove the succinimide formed by extraction with water. For this purpo~e, from 10 to 100% by weight of water, based on reaction mixture, are usually used.
A particularly simple and at the same time effective method of removing succinimide is to separate the succi-nimide formed from the reaction mixture in a first step by filtration and in a second step by extraction with water. This uses comparatively little water and accor-dingly also gives little wastewater.
The bromination carried out under the action of lightgives the desired product in a yield of about 80 %. In addition, it usually gives from 1 to 6 % of a brominated substance, pre~umably 2-bL~.o_.cthyl-2'-methyl-1,1'-binaphthyl, and from 7 to 13 % of a further byproduct,presumably 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
The correspon~i ng reaction mixture (A) used in the Arbusov reaction presumably contains, besides small amounts of substances not identified in more detail, the abovementioned bromo compounds dissolved in the solvent, for example in chlorobenzene and/or dichlorobenzene, in particular in chlorobenzene.
In place of the reaction mixture (A) prepared under the 21~525S-action of light, it is also possible to use a reaction mixture (B) which can be obtained, for example, by reaction of 2,2'-dimethyl-1,1'-binaphthyl with N-bromo-succinimide in the presence of a solvent under the action of a free-radical former (free-radical initiator) and by subæequent removal of succinimide, with good results in the Arbusov reaction (reaction with the alkyl diphenyl-phosphinite). Such a reaction mixture (B) can be prepared by reacting 2,2'-dimethyl-1,1'-binaphthyl with N-bromo-succinimide, for example in a molar ratio of 1:(1.5 to2.5), in particular 1:(1.8 to 2.3), preferably 1:(1.9 to 2.2), at elevated temperature, usually at temperatures of from 25 to 150C, in particular from 40 to 135C, under the action of a free-radical initiator in chlorobenzene and/or dichlorobenzene, removing ~uccinimide formed, but without removing the chlorobenzene and/or dichlorobenzene used as solvent.
Suitable free-radical initiators are the customary free-radical formers, for example organic peroxides, hydro-peroxides, azobisisobutyronitrile.
The bromination carried out under the action of the free-radical initiator gives the desired product in a yield of from about 63 to 67 %. In addition, it generally gives from 10 to 20 % of a brominated product, presumably 2-bromomethyl-2'-methyl-1,1'-binaphthyl, and from 8 to 15 % of a further byproduct, presumably 2-dibromomethyl-2-bromomethyl-1,1'-binaphthyl. The reaction mixture (B) used in the Arbusov reaction presumably contains, besides small amounts of substances not identified in more detail, the abovementioned bromo compounds dissolved in chlorobenzene and/or dichlorobenzene, in particular chlorobenzene.
The ~uccinimide formed from the N-bromosuccinimide is separated from the bromination mixture, if desired after cooling, by filtration. Another possibility is to carry out the subsequent removal of succinimide by extraction with water.
21~525~
g A particularly simple and effective variant is to separate succinimide from the bromination mixture in a first step by filtration and in a second step by extraction with water.
Unreacted free-radical formers can be removed, for example, by scrubbing with an aqueous Na2S03 solution.
The abovedescribed procedure gives the reaction mixture (B).
To carry out the Arbusov reaction, the reaction mixture, for example the reaction mixture (A) or the reaction mixture (B), is reacted with an alkyl diphenylphosphinite (formula IV), as already mentioned above, at from 70 to 180C. In many cases, it is sufficient to carry out the reaction at from 100 to 170C, in particular from 120 to 160C. The reaction proceeds according to the following equation:
I ~ l~e, ~ ~ h - ( 11 ) " ) 2 Ito-~(~h-(~ [~ ;(Fh-(R')")~
( I I I ) ( lV) ( 10) The alkyldiphenylphosphinite of the formula (IV) uRed is usually a (Cl-C5)alkyl diphenylphosphinite or a mixture of these esters. Suitable alkyl diphenylphosphinites are, without claiming completene~, methyl diphenylphos-phinite, ethyl diphenylphosphinite, isopropyl diphenyl-phosphinite, n-propyl diphenylphosphinite, ethyl bis(3-fluorophenyl)phosphinite, ethyl bis(4-fluorophenyl)-phosphinite, ethyl bis(2-methylphenyl)phosphinite and/or ethyl bis(3-trifluoromethylphenyl)phosphinite.
The alkyl diphenylphosphinite is generally used in a 21 ~5~55 molar ratio of (1.8 to 4):1, in particular (1.9 to 3):1, preferably (2 to 2.5):1, based on the 2,2'-dimethyl-1,1'-binaphthyl. However, in many cases it is possible to use the alkyl diphenylphosphinite (formula IV), based on 2,2'-dimethyl-1,1'-binaphthyl used, in the stoichiometric ratio or in a slight excess.
Before the reaction mixture resulting from the bromina-tion stage is used in the subseguent Arbusov reaction (reaction with the alkyl diphenylphosphinite), it is advisable, as mentioned above, in many cases to remove the unreacted brominating agent and/or the reacted brominating agent and/or the solvent used in the bromina-tion stage.
Unreacted brominating agent, for example bromine, can be removed by vaporization, reacted brominating agent, for example succinimide, can be removed by filtration and extraction. The solvent used in the bromination stage is replaced by a further solvent which has a boiling point higher than that of the solvent originally used. The further solvent is added prior to the reaction or during the reaction or after the reaction of the reaction mixture with the alkyl diphenylphosphinite and the solvent originally used is subsequently distilled off.
This removal of the original solvent can be carried out prior to the Arbusov reaction or even during the Arbusov reaction or after the Arbusov reaction. If a solvent which is inert to the Arbusov reaction is used as ori-ginal solvent, it can be removed during the Arbusov reaction or the removal can even be omitted. Such sol-vents are, for example, chlorobenzene, dichlorobenzeneand mixtures thereof; when they are used a removal i~ not absolutely necessary.
Solvents which are not inert to the Arbusov reaction have to be removed prior to carrying out the Arbusov reaction.
Such solvents are, for example, monochlorinated or polychlorinated aliphatic hydrocarbons.
Suitable further solvents are generally solvents which have a boiling point higher than that of the solvent originally used and which are inert under the conditions of the Arbusov reaction. These include aromatic hydrocar-bons, for example toluene, o-xylene, m-xylene, p-xylene, mixtures of these xylenes, ethylbenzene and/or me~itylene and high-boiling aliphatic hydrocarbons, for example petroleum ether having a boiling point ~ 100C, decalin, ligroin and/or isooctane.
The Arbusov reaction can thus be carried out in the presence or absence of a further solvent.
In some cases it has been found to be advantageous to add the further, nonpolar solvent which has a boiling point higher than that of the solvent originally used during the Arbusov reaction (reaction with the alkyl diphenyl-phosphinite) and to simultaneously distill off the solvent originally used, for example chlorobenzene and/or dichlorobenzene. Suitable solvents for this purpose are, for example, aromatic compounds having boiling points higher than chlorobenzene and/or dichlorobenzene, for example o-xylene, m-xylene, p-xylene, mixtures of these xylenes and/or mesitylene. This allows the yield of 2,2'-bis(diphenylphosphinylmethyl)-l,1'-binaphthylisolatedto be increased somewhat further.
It is surprising that the brominated binaphthyls, for example the brominated byproducts present in both the reaction mixture (A) and in the reaction mixture (B) generally do not interfere in the Arbusov reaction and also do not impair the quality of the desired final product (formula I). Furthermore, it i~ unexpected that the use of a solvent, for example the use of chloroben-zene and/or dichlorobenzene, in the Arbusov reactionleads to a significant increaRe in yield. While the process of JP 7 939 059 gives a yield of only 30 %, the process of the invention gives a yield of from 90 to 95 %
of desired product, in each case based on 2,2'-bis(bromo-methyl)-1,1'-binaphthyl. In addition, the danger of the reaction occurring explosively is avoided.
21~5~5~
To carry out the Arbusov reaction, the reaction mixture, for example reaction mixture (A) or the reaction (B) or mixtures of the two reaction mixtures, is usually initially charged and heated to the prescribed tem-perature. It is advantageous to select a temperaturebelow the boiling point of the solvent used. After reaching the reaction temperature, the alkyl diphenyl-phosphinite is 610wly added dropwise to the initially charged reaction solution. As the reaction proceeds, it results in the formation of alkyl bromide which is continuously distilled from the reaction product. If desired, the mixture can also be boiled under reflux for some time after the end of the addition of the alkyl diphenylphosphinite, 80 as to complete the reaction.
If it is intended that the solvent originally used be removed during the Arbusov reaction, a temperature above the boiling point of the original solvent but below that of the further solvent added is selected. In this way, both the alkyl bromide and also the solvent originally used distills off.
The process of the invention makes it possible to obtain the new compounds of the formula (Ia) ~R') (~/ )2 )2 where R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine, in particular methyl, CF3 or fluorine, and n i8 1 or 2, in a sur-prisingly simple manner by reaction of 2,2'-bis(bromo-methyl)-1,1'-binaphthyl of the formula (III) with the corresponding diphenylphosphinic ester of the formula IV.
New compounds in this category which may be mentioned are, in particular, 2,2'-bis[bis(3-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl, 2,2'-bis[bis(4-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl, 2,2'-bis[bis(2-methylphenyl)phosphinylmethyl]-1,1'-binaphthyl and 2,2'-bis[bis(3-trifluoromethylphenyl)phosphinylmethyl]-l,l'-binaphthyl.
The following examples illustrate the invention without limiting it.
Experimental part:
Example 1 Preparation using a reaction mixture A
With exclusion of moisture, 282.4 g (1.0 mol) of 2,2'-dimethyl-l,l'-binaphthyl and 373.8 g (2.1 mol) of N-bromosuccinimide are suspended in 1.7 1 of chloro-benzene in a 4 1 glass flask and are illuminated with a W immersion lamp for 8 hours at from 5 to 10C. The precipitated succinimide is filtered off, the solution is extracted twice with 200 ml of water each time, dried using sodium sulfate and filtered. The filtrate (reaction mixture A) is transferred to a 4 l four-neck flask fitted with stirrer, dropping funnel, reflux condenser and internal thermometer and is heated to 125C. 460.5 g (2.0 mol) of ethyl diphenylphosphinite are then slowly added dropwise, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C.
The solid is filtered off, washed with cold chlorobenzene and dried in vacuo. This gives 512 g (purity: ~ 99 %) of 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyl as colorless crystals having a melting point of from 287 to 21~52~
289C, correspo~;ng to 75 % total yield based on 2,2'-dimethyl-1,1'-binaphthyl used.
Composition according to GC analysis (in mol %) without solvent:
80 % of 2,2'-bis(bLu~.u~.cthyl)-l,l'-binaphthyl 2 % of 2-bromomethyl-2'-methyl-1,1'-binaphthyl 13 % of 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
Example 2 Preparation using a reaction mixture A
With exclusion of moisture, 282.4 g (1.0 mol) of 2,2'-dimethyl-1,1'-binaphthyl and 373.8 g (2.1 mol) of N-bromosuccinimide are suspended in 1.7 1 of chloro-benzene in a 4 1 glass flask and are illuminated with a W immersion lamp for 8 hours at from 5 to 10C. The precipitated succinimide is filtered off, the solution i8 extracted twice with 200 ml of water each time, dried using sodium sulfate and filtered. The filtrate (reaction mixture A) is transferred to a 4 1 four-neck flask fitted with stirrer, dropping funnel, reflux condenser and internal thermometer and i8 heated to 125C. 488.6 g (2.0 mol) of propyl diphenylphosphinite are then slowly added dropwise, with n-propyl bromide distilling off.
After the end of the addition, the mixture is heated under reflux for a further two hours and iæ then cooled to 0C. The solid is filtered off, washed with cold chlorobenzene and dried in vacuo. This gives 502.5 g of 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyl (purity: ~ 99 ~) as colorless crystals having a melting point of from 287 to 289C, correspo~;ng to 73.5 % total yield based on 2,2'-dimethyl-1,1'-binaphthyl used.
Composition according to GC analysis (in mol %) without solvent:
68 % of 2,2'-bis(bromomethyl)-1,1'-binaphthyl 15 % of 2-bromomethyl-2'-methyl-1,1'-binaphthyl 13 % of 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
Example 3 Preparation using a reaction mixture B
With exclusion of moisture, 282.4 g (1.0 mol) of 2,2'-dimethyl-l,l'-binaphthyl, 373.8 g (2.1 mol) of N-bromosuccinimide and 500 mg of benzoyl peroxide are suspended in 1.7 1 of chlorobenzene in a 4 1 glass flaæk and are stirred for 3.5 hours at the boiling point. The precipitated succinimide is filtered off, the solution is extracted twice with 200 ml of water each time and once with 100 ml of Na2S03 solution, dried using sodium sulfate and filtered. The filtrate (reaction mixture B) is transferred to a 4 1 four-neck flask fitted with stirrer, dropping funnel, reflux condenser and internal thermometer and is heated to 125C. 460.5 g (2.0 mol) of ethyl diphenylphosphinite are then slowly added dropwise, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold chlorobenzene and dried in vacuo. This gives 443.8 g (purity: ~ 99 %) of 2,2'-bis-(diphenylphosphinylmethyl)-l,l'-binaphthyl as colorless crystals having a melting point of from 287 to 289C, correspon~;n~ to 65 % total yield based on 2,2'-dimethyl-l,l'-binaphthyl used.
Composition according to GC analysis (in mol %) without solvent:
68 ~ of 2,2'-bi 5 (bromomethyl)-1,1'-binaphthyl 15 % of 2-bromomethyl-2'-methyl-1,1'-binaphthyl 13 % of 2-dibromomethyl-2'-bromomethyl-1,1'-binaphthyl.
21 4525~
Example 4 2,2'-Bis[bis(3-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl While stirring under nitrogen, 8.8 g (33 mmol) of ethyl bis(3-fluorophenyl)phosphinite are slowly added dropwise to a solution of 7.27 g (16.6 mmol) of 2,2'-bis(bromo-methyl)-l,l'-binaphthyl in 40 ml of o-xylene, which solution has been heated to 120C, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold o-xylene and dried in vacuo. This gives 11.5 g (91 %) of colorless crystals having a melting point of 280-284C.
31P-NMR: ~ (CDCl3) = 27.3 ppm Example 5 2,2'-Bis[bis(4-fluorophenyl)phosphinylmethyl]-1,1'-binaphthyl While stirring under nitrogen, 10.70 g (0.04 mol) of ethyl bis(4-fluorophenyl)phosphinite are added dropwise to a solution of 8.80 g (0.02 mol) of 2,2'-bis(bromo-methyl)-l,l'-binaphthyl in 40 ml of o-xylene, which solution has been heated to 135C. After the end of the addition, the mixture is heated under reflux for a further 1.5 hours. After cooling to room temperature, the precipitated crystals are filtered off with suction and wa~hed with xylene. This give~ 14.1 g (94 %) of colorle~s crystals having a melting point of 211-214C.
31P-NMR: ~ (CDCl3) = 28.2 ppm 21~525-~
Example 6 2,2'-Bis~bis(2-methylphenyl)phosphinylmethyl]-1,1'-bi-naphthyl While stirring under nitrogen, 21.5 g (83 mmol) of ethyl bis(2-methylphenyl)phosphinite are slowly added dropwise to a solution of 18.4 g (42 mmol) of 2,2'-bis(bromo-methyl)-1,1'-binaphthyl in 100 ml of o-xylene, which solution has been heated to 120C, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold o-xylene and dried in vacuo. This gives 25.1 g (81 %) of colorless crystals having a melting point of 231-234C.
31P-NMR: ~ (CDCl3) = 30.5 ppm Example 7 2,2'-Bis[bis(3-trifluoromethylphenyl)phosphinylmethyl]-1,1'-binaphthyl While stirring under nitrogen, 20.1 g (55 mmol) of ethyl bis(3-trifluoromethylphenyl)phosphinite are slowly added dropwise to a solution of 11.0 g (25 mmol) of 2,2'-bis(bromomethyl)-1,1'-binaphthyl in 80 ml of o-xylene, which solution has been heated to 120C, with ethyl bromide distilling off. After the end of the addition, the mixture is heated under reflux for a further two hours and i8 then cooled to 0C. The solid i9 filtered off, washed with cold o-xylene and dried in vacuo. This gives 16.1 g (68 %) of colorless crystals.
31P-NMR: ~ (CDCl3) = 27.1 ppm Example 8 (Arbusov in ethyl acetate) While stirring under nitrogen, 88.5 g (385 mmol) of ethyl 21~52~5 diphenylphosphinite are slowly added dropwise to a solution of 77.0 g (I75 mmol) of 2,2'-bis(bromomethyl)-1,1'-binaphthyl in 400 ml of ethyl acetate, which 801u-tion has been heated to 78C, and ethyl bromide is simultaneously distilled off via an 80 cm Vigreux column.
After the end of the addition, the mixture i8 heated under reflux for a further two hours and is then cooled to 0C. The solid is filtered off, washed with cold ethyl acetate and dried in vacuo. This gives 85.0 g (71 %) of colorless crystals having a melting point of 287-289C.
Claims (22)
1. A process for preparing 2,2'-bis(diphenylphosphinyl-methyl)-1,1'-binaphthyls, which comprises reacting a reaction mixture prepared in a 601vent by reaction of 2,2'-dimethyl-1,1'-binaphthyl with a brominating agent and containing 2,2'-bis(bromomethyl)-1,1'-binaphthyl and further brominated binaphthyls, if desired after removal of unreacted brominating agent, reacted brominating agent and/or solvent, with an alkyl diphenylphosphinite of the formula RO-P(Ph-(R')n)2, where R is an alkyl radical having from 1 to 5 carbon atoms, Ph is phenyl, R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine and n is 0, 1 or 2, at from 70 to 180°C in the presence or absence of a further solvent.
2. The process as claimed in claim 1, wherein 2,2'-dimethyl-1,1'-binaphthyl and the solvent are used in a weight ratio of 1:(3 to 40), in particular 1:(4 to 20), preferably 1:(5 to 15).
3. The process as claimed in claim 1 or 2, wherein the solvent used is a monochlorinated or polychlorinated benzene, a monochlorinated or polychlorinated aliphatic hydrocarbon, an ester of an aliphatic carboxylic acid having from 1 to 6 carbon atoms and an aliphatic alcohol having from 1 to 4 carbon atoms or a mixture thereof.
4. The process as claimed in one or more of claims 1 to 3, wherein the solvent used is chlorobenzene or dichlorobenzene.
5. The process as claimed in one or more of claims 1 to 3, wherein the solvent used is a mixture of chloro-benzene and dichlorobenzene.
6. The process as claimed in one or more of claims 1 to 5, wherein 2,2'-dimethyl-1,1'-binaphthyl and the brominating agent are reacted under the action of light having a wavelength of from 10-5 to 10-8 m at from -10 to 75°C, in particular from -5 to +50°C, preferably from 0 to 40°C.
7. The process as claimed in one or more of claims 1 to 5, wherein 2,2'-dimethyl-1,1'-binaphthyl and the brominating agent are reacted under the action of a free-radical former at from 25 to 150°C, in particu-lar from 40 to 135°C.
8. The process as claimed in one or more of claims 1 to 7, wherein 2,2'-dimethyl-1,1'-binaphthyl is reacted with N-bromosuccinimide as brominating agent.
9. The process as claimed in one or more of claims 1 to 8, wherein 2,2'-dimethyl-1,1'-binaphthyl and N-bromosuccinimide are used in a molar ratio of 1:(1.5 to 2.5), in particular 1:(1.8 to 2.3), pre-ferably 1:(1.9 to 2.2).
10. The process as claimed in one or more of claims 6 to 9, wherein the succinimide formed as reacted bromi-nating agent is removed after bromination.
11. The process as claimed in one or more of claims 6 to 10, wherein succinimide is removed, if desired after cooling, by filtration.
12. The process as claimed in one or more of claims 6 to 11, wherein succinimide is removed by extraction with water.
13. The process as claimed in one or more of claims 6 to 12, wherein succinimide is removed in a first step by filtration and in a second step by extraction with water.
14. The process as claimed in one or more of claims 1 to 13, wherein the reaction mixture is reacted with the alkyl diphenylphosphinite of the formula RO-P(Ph-(R')n)2 at from 100 to 170°C, in particular from 120 to 160°C.
15. The process as claimed in one or more of claims 1 to 14, wherein the alkyl diphenylphosphinite of the formula RO-P(Ph-(R') n) 2 is used in a molar ratio of (1.8 to 4):1, in particular (1.9 to 3):1, preferably (2 to 2.5):1, based on 2,2'-dimethyl-1,1'-binaphthyl used.
16. The process as claimed in one or more of claims 1 to 15, wherein the alkyl diphenylphosphinite of the formula RO-P(Ph-(R')n)2 which is used is a (C1-C5)-alkyl diphenylphosphinite or a mixture of these esters.
17. The process as claimed in one or more of claims 1 to 16, wherein the alkyl diphenylphosphinite of the formula RO-P(Ph-(R')n)2 which is used is methyl diphenylphosphinite, ethyl diphenylphosphinite, isopropyl diphenylphosphinite, n-propyl diphenyl-phosphinite, ethyl bis(3-fluorophenyl)phosphinite, ethyl bis(4-fluorophenyl)phosphinite, ethyl bis(2-methylphenyl)phosphinite and/or ethyl bis(3-tri-fluoromethylphenyl)phosphinite.
18. The process as claimed in one or more of claims 1 to 17, wherein a further solvent which has a boiling point higher than that of the solvent originally used is added prior to the reaction or during the reaction or after the reaction of the reaction mixture with the alkyl diphenylphosphinite and the solvent originally used is distilled off.
19. The process as claimed in one or more of claims 1 to 17, wherein o-xylene, m-xylene, p-xylene, mixtures of these xylenes and/or mesitylene are added as a further solvent during the reaction of the reaction mixture with the alkyl diphenylphosphinite and chlorobenzene and/or dichlorobenzene are distilled off as the solvent originally used.
20. A compound of the formula where R' is an alkyl radical having from 1 to 4 carbon atoms, CF3, fluorine, chlorine or bromine and n is 1 or 2.
21. A compound of the formula where R' is methyl, CF3 or fluorine and n is 1 or 2.
22. The compounds 2,2'-bis[bis(3-fluorophenyl)phos-phinylmethyl]-1,1'-binaphthyl, 2,2'-bis[bis(4-fluo-rophenyl)phosphinylmethyl]-1,1'-binaphthyl, 2,2'-bis[bis(2-methylphenyl)phosphinylmethyl]-1,1'-bi-naphthyl and 2,2'-bis[bis(3-trifluoromethylphenyl)-phosphinylmethyl]-1,1'-binaphthyl.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4409973.8 | 1994-03-23 | ||
| DE4409973 | 1994-03-23 | ||
| DE4433295A DE4433295A1 (en) | 1994-03-23 | 1994-09-19 | Process for the preparation of 2,2'-bis (diphenylphosphinylmethyl) -1,1'-binaphthylene and new compounds from this group of substances |
| DEP4433295.5 | 1994-09-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2145255A1 true CA2145255A1 (en) | 1995-09-24 |
Family
ID=25934985
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002145255A Abandoned CA2145255A1 (en) | 1994-03-23 | 1995-03-22 | Process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substances |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0673944B1 (en) |
| JP (1) | JP3761213B2 (en) |
| AT (1) | ATE204284T1 (en) |
| AU (1) | AU701242B2 (en) |
| CA (1) | CA2145255A1 (en) |
| ES (1) | ES2161791T3 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10114868C1 (en) | 2001-03-26 | 2002-10-31 | Oxeno Olefinchemie Gmbh | Process for the preparation of diphosphines and their use |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2092737T3 (en) * | 1992-10-29 | 1996-12-01 | Hoechst Ag | PROCEDURE FOR THE PREPARATION OF BROMOMETIL-AROMATIC COMPOUNDS. |
-
1995
- 1995-03-09 EP EP95103403A patent/EP0673944B1/en not_active Expired - Lifetime
- 1995-03-09 AT AT95103403T patent/ATE204284T1/en not_active IP Right Cessation
- 1995-03-09 ES ES95103403T patent/ES2161791T3/en not_active Expired - Lifetime
- 1995-03-15 AU AU14849/95A patent/AU701242B2/en not_active Ceased
- 1995-03-22 JP JP06308995A patent/JP3761213B2/en not_active Expired - Fee Related
- 1995-03-22 CA CA002145255A patent/CA2145255A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU701242B2 (en) | 1999-01-21 |
| EP0673944B1 (en) | 2001-08-16 |
| ES2161791T3 (en) | 2001-12-16 |
| EP0673944A1 (en) | 1995-09-27 |
| AU1484995A (en) | 1995-10-05 |
| ATE204284T1 (en) | 2001-09-15 |
| JPH0841086A (en) | 1996-02-13 |
| JP3761213B2 (en) | 2006-03-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Konno et al. | Facile syntheses of various per-or polyfluoroalkylated internal acetylene derivatives | |
| Yamato et al. | Organic reactions catalyzed by solid superacids. 10. Perfluorinated sulfonic acid resin (Nafion-H) catalyzed ring closure reaction of 2, 2'-diaminobiphenyls. A preparative route to carbazoles | |
| JP6968067B2 (en) | Arylization method | |
| US5767317A (en) | Process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substances | |
| CA2145255A1 (en) | Process for preparing 2,2'-bis(diphenylphosphinylmethyl)-1,1'-binaphthyls and new compounds from this class of substances | |
| US5616787A (en) | Process for the preparation of alkylated aromatic carboxylic acids and acyl halides | |
| KR20190116350A (en) | New synthesis method of 1-aryl-1-trifluoromethylcyclopropane | |
| KR20040013005A (en) | Process for the production of pentaerythritol phosphate alcohol | |
| AU702642B2 (en) | Process for preparing 2,2'-bis(halomethyl)-1,1'-binaphthyl | |
| US5177238A (en) | Preparation of dialkyl allylphosphonic acid diesters | |
| CN113272286B (en) | Process for preparing 4- (2, 3-tetrafluoropropyl) morpholine | |
| JPS5949207B2 (en) | Diene manufacturing method | |
| JPH07187627A (en) | Fulleren derivatives, their preparation and their use | |
| US4816605A (en) | Process for the preparation of bifunctional tertiary aromatic phosphine oxides | |
| US5470998A (en) | Process for the preparation of esters of stilbenedicarboxylic acid | |
| EP0008446B1 (en) | Process for the preparation of carbazoles and novel carbazole derivatives utilized therein | |
| US2602823A (en) | Alpha-bromoethylpentachloro-benzene | |
| US2877251A (en) | Aliphatic and aromatic phosphorus-mercury compounds and method of preparing same | |
| KR960001703B1 (en) | Ñô-fluoracyl-ñô-halogen vinyl alkyl ethers | |
| JP3978690B2 (en) | Method for synthesizing methyl-1,1-dichloromethyl ether or ethyl-1,1-dichloromethyl ether | |
| US5473095A (en) | Process for the preparation of chlorinated 4,5-difluorobenzoic acids, -benzoic acid derivatives and -benzaldehydes | |
| CS220713B1 (en) | Dialkylesters acids of the p-toluensulfonyloxymethanforfon and method of preparation of the same | |
| US4122115A (en) | Preparation of chloro- and bromo-fluoroacetyl chloride | |
| JP3014231B2 (en) | Method for producing organic phosphorus compound | |
| SU444357A1 (en) | The method of obtaining 1,1-dihalo3-arylpropen-1 |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |