JP5638862B2 - Biaryl compound production method and microwave reaction catalyst usable therefor - Google Patents

Description

  The present invention relates to an efficient method for producing a biaryl compound using microwave irradiation and a supported palladium catalyst, and a supported palladium catalyst for microwave reaction that can be used therefor.

  So far, biaryl compounds have been produced using, for example, the Suzuki-Miyaura reaction in which an organoboron compound and an aryl halide are reacted in the presence of a palladium catalyst. However, the reaction takes a long time and the amount of solvent used is large. Therefore, there has been a demand for an efficient manufacturing method such as switching to a reaction system using microwave irradiation in consideration of environmental burdens.

  However, the palladium catalyst used in the usual Suzuki-Miyaura reaction and the like is not necessarily sufficient in terms of catalytic activity and the like in a reaction system using microwave irradiation, and therefore a new palladium catalyst is required. It was.

  By the way, porous silica is an excellent material as a carrier for a catalyst because it has various pore structures and a wide surface area. On the other hand, carbon-based materials generally have a large dielectric loss coefficient, which is an index of microwave absorption characteristics, and have characteristics of being easily heated by absorbing microwaves. Therefore, a porous silica carrier containing an appropriate amount of carbon component is used. There is a possibility that the supported metal catalyst produced in this way can be effectively used in the reaction under microwave irradiation. In particular, those in which the catalyst metal is palladium can be expected to be applied to various reactions such as the Suzuki-Miyaura reaction and the Sonogashira reaction.

  However, most of the palladium catalysts used for microwave reactions are homogeneous and heterogeneous using a polymer as a carrier. In fact, the Suzuki-Miyaura reaction is related to microwave irradiation and homogeneous systems. Production examples of biaryl compounds by a cross-coupling reaction between an aryl halide or aryl triflate and an aryl boronic acid derivative using a catalyst have been reported (Non-Patent Documents 1 to 4), but carbon component-containing porous silica No one has been known that uses a supported palladium catalyst with a carrier.

  On the other hand, since it is difficult to separate, recover and reuse the catalyst in the homogeneous reaction, an example of a reaction system using microwave irradiation using a heterogeneous supported palladium catalyst which is industrially advantageous has been reported. As such reports, for example, in the heterogeneous Suzuki-Miyaura reaction, a reaction example using polyethylene or polystyrene as a carrier (Non-Patent Document 5), a chloromethylated polystyrene-divinylbenzene polymer / glass composite as a carrier is used. Reaction examples (Non-patent Document 6), and reaction examples (Non-Patent Document 7) using polystyrene-maleic anhydride copolymer as a carrier.

  However, the heterogeneous supported palladium catalyst used in these reported examples has low thermal stability because it uses a polymer as a support, or when the support is polyethylene, it has high functionality by surface modification. There were problems such as being difficult. In addition, since it is not always clear to those skilled in the art what kind of physical properties and physical properties are suitable for a reaction system using microwave irradiation, an excellent supported palladium catalyst used in a heterogeneous system. The situation was not proposed.

  In general, in a reaction using a catalyst, it is necessary to activate the catalyst by heating or the like. However, in a reaction system using microwave irradiation, the catalyst is heated by dielectric heating unlike normal external heating (non-patent) According to Document 8), unless a catalyst having a preferable physical property such as a dielectric loss coefficient is used, the catalyst is not heated well and the catalyst cannot be activated. Therefore, when conventional catalysts are used in a reaction system using microwave irradiation, it may be difficult to control the activity / selectivity of the catalyst, or the decomposition / deactivation of the catalyst may occur. Although a point arises, the fact that the catalyst which solved it is not proposed.

J. et al. Org. Chem. 61, 9582 (1996) Org. Lett. 4, 2973 (2002) Green Chem. , 5,615 (2003) Tetrahedron, 61, 9349 (2005) Org. Lett. , 6, 2793 (2004) Tetrahedron, 61, 12121 (2005) Tetrahedron, 61, 12168 (2005) Chem. Soc. Rev. , 27, p. 213 (1998)

  The present invention has been made in view of the circumstances as described above, and provides an efficient method for producing a biaryl compound using microwave irradiation and a supported palladium catalyst, and for a microwave reaction that can be used for this method. The purpose is to provide a highly efficient catalyst.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained a supported palladium catalyst having a specific dielectric loss coefficient, particularly a supported palladium catalyst having a specific dielectric loss coefficient and composition, and a method for producing a biaryl compound. As a result, the present inventors have found that a biaryl compound can be produced efficiently by using the present invention, thereby completing the present invention.

That is, in the present invention, palladium is supported on porous silica and irradiated with microwaves in the presence of a supported palladium catalyst having a dielectric loss coefficient of 0.1 to 3.0, and the following general formula (I)
RX (I)
(In the formula, R represents a monovalent aryl group, X represents a halogen atom or trifluoromethanesulfonyloxy group selected from bromine, iodine and chlorine atoms. A group in which some of the hydrogen atoms of the aryl group do not participate in the reaction) Can be replaced with.)
An aryl halide or aryl triflate represented by the following general formula (II)
R'B (OR ") ₂ (II)
(In the formula, R ′ represents a monovalent aryl group, R ″ represents a hydrogen atom or an alkyl group. When two R ″ in the molecule are alkyl groups, they are bonded at the end to form a cyclic compound. It does not matter if it is.)
A cross-coupling reaction with an arylboronic acid derivative represented by the following general formula (III)
RR '(III)
(In the formula, R and R ′ have the same meaning as described above.)
Is a method for producing a biaryl compound represented by the formula:

  Further, the present invention provides a carbon component produced by firing a porous silica precursor containing an organic template component at a temperature of 400 ° C. or higher in an inert gas atmosphere. A supported palladium catalyst for microwave reaction, characterized in that the carbon-containing porous silica contained is simply “%” and the dielectric loss coefficient after palladium is supported is 0.1 to 3.0. .

  In the method for producing a biaryl compound of the present invention, a reaction by microwave irradiation can be efficiently performed by using a supported palladium catalyst having a specific dielectric loss coefficient.

  In addition, the supported palladium catalyst for microwave reaction of the present invention exhibits higher catalytic activity in the reaction under microwave irradiation than when the reaction is performed under normal heating conditions such as an oil bath or an aluminum block. As a result, the target product can be obtained in a high yield even in a short time.

Palladium is supported on porous silica used as a catalyst in the method for producing the biaryl compound of the present invention (hereinafter referred to as “the present invention process”), and the dielectric loss coefficient thereof is 0.1 to 1.5. The palladium catalyst (hereinafter referred to as “the catalyst of the present invention”) is made from porous silica as a raw material. As long as the porous silica is a silica having a large number of pores, the form, shape, particle diameter, specific surface area, average pore diameter and the like are not particularly limited, but are preferably 100 to 1500 m ² / g, more preferably 200. A silica having a specific surface area of ˜1200 m ² / g, preferably 0.5 to 500 nm, more preferably 1 to 100 nm. Examples of such porous silica include those commercially available as CARiACT Q-3, CARiACT Q-10 (both manufactured by Fuji Silysia Chemical Co., Ltd.) and the like, as well as SBA-15 and MCM- prepared as follows. 41, porous silica having a basic structure such as MCM-48, MCM-50, FSM-16, and FSM-22.

  Porous silica having a basic structure such as SBA-15, MCM-41, MCM-48, MCM-50, FSM-16, FSM-22 or the like is a conventionally known method using an organic template component and a silica source (for example, J. Am. Chem. Soc., 114, 10834 (1992), Bull. Chem. Soc. Jpn., 69, 1149 (1996), J. Am. Chem. Soc., 120, 6024 (1998), Angew. Chem. Int. Ed., 45, 3216 (2006)).

  Specifically, to prepare porous silica having the basic structure of MCM-41, MCM-48, MCM-50, FSM-16 or FSM-22 among the above porous silica, as an organic template component, for example, Quaternary ammonium salts having a long chain alkyl group such as hexadecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, docosyltrimethylammonium chloride, etc., and tetraethoxysilane, tetramethoxysilane as a silica source Tetrapropoxysilane or the like may be used.

  On the other hand, in order to prepare porous silica having a basic structure of SBA-11, SBA-12, SBA-15 or SBA-16, as an organic template component, for example, Brij30, Brij52, Brij56, Tween20, Tween40, Tween60, Tetraethoxysilane is used as a silica source using a surfactant having a poly (ethylene oxide) (PEO) skeleton such as Tween 80, Triton X114, Tergitol TMN6, or a block copolymer such as Pluronic P123, Pluronic L121, Tetronic 908 or the like. Tetramethoxysilane, tetrapropoxysilane, or the like may be used.

  In order to prepare porous silica using the organic template component and the silica source, for example, the organic template component and the silica source (the mass ratio thereof is usually 1: 0.5 to 1:10) are reacted in an acidic aqueous solution. The porous silica precursor obtained by heating is put into a heating apparatus such as an electric furnace, and the temperature is 400 ° C. or higher, preferably 400 to 600 ° C. for 3 to 10 hours in air or in an inert gas atmosphere such as nitrogen or argon. What is necessary is just to bake. When calcination is performed in the air, basically, porous silica containing almost no carbon or a small amount of carbon is obtained.

  The porous silica used in the production method of the present invention may not contain a carbon component, but the porous silica contains carbon containing 0.1 to 5%, preferably 0.1 to 4% of the carbon component. Use of silica (hereinafter referred to as “carbon-containing porous silica”) is preferable because it gives the catalyst high activity and stability, and furthermore, the amount of electric power per mole of the product is small. Such carbon-containing porous silica can be prepared by controlling the firing temperature, time, air flow rate of the inert gas, and the like during the firing. The firing temperature is 400 ° C. or higher, preferably 400 to 600 ° C., the time is 3 to 10 hours, preferably 3 to 7 hours, and the air velocity is 10 to 1000 mL / min, preferably Is 30-800 mL / min. For example, the lower the firing temperature, the shorter the time, and / or the lower the air velocity, the more the carbon component content tends to increase.

  Carbon-containing porous silica has a dielectric loss coefficient of an appropriate size and has the ability to absorb microwaves appropriately. Therefore, if palladium is supported on this, various types of microbes using a palladium catalyst are used. It can be used in a normal usage amount in a reaction system using wave irradiation. Examples of such reactions include various reactions involving carbon-carbon bond formation known as Suzuki-Miyaura reaction, Sonogami reaction, Heck reaction, Stille reaction, etc., and Buchwald-Hartwig ( Buchwald-Hartwig) reaction known as carbon-nitrogen bond and carbon-oxygen bond generation can be exemplified.

  The porous silica prepared as described above is used as it is or after being modified with an appropriate organic group such as polyethylene glycol group, hydroxyalkyl group, phosphinoalkyl group, aminoalkylsilyl group according to a conventional method. You can also

  For supporting palladium on the porous silica, a conventionally known method such as a liquid phase method or a gas phase method may be used. As the liquid phase method, for example, a method in which a support and an appropriate palladium compound are mixed and concentrated in a solution to adsorb the palladium compound on the support can be used. Examples of the palladium compound used in the liquid phase method include palladium salts, palladium complexes, and the like. Specifically, palladium acetate, palladium chloride, palladium bromide, allyl palladium chloride dimer, bis (benzonitrile) dichloropalladium, etc. Is mentioned. The solvent used in the liquid phase method is not particularly limited as long as it is a solvent capable of dissolving a palladium compound. However, when using a palladium complex such as palladium acetate, it is preferable to use tetrahydrofuran having good solubility. preferable. On the other hand, prepared by vapor deposition of palladium complexes (palladium complexes that can be sublimated and purified) such as palladium acetate, allyl (cyclopentadienyl) palladium, and bis (acetylacetonato) palladium under vacuum on a carrier. You can also In addition, the palladium amount in the catalyst of the present invention is usually 0.001 to 10%, preferably 0.01 to 5%.

The catalyst of the present invention thus prepared has a dielectric loss coefficient of 0.1 to 3.0, preferably 0.1 to 1.5, more preferably 0.1 to 1.4, and particularly preferably 0.7. ~ 1.2. When the dielectric loss coefficient of the supported palladium catalyst is larger than 3.0, the catalyst may be heated too much by microwave irradiation, which may cause decomposition / deactivation of the catalyst. Since microwave absorption is very small, an efficient heating / activation effect cannot be expected. Note that the value of the dielectric loss coefficient varies depending on the measurement frequency, but considering the application to a chemical process using a microwave, it is important to have the above value at 0.3 to 30 GHz. Further, in this frequency region, it is preferable to have a dielectric loss coefficient in the above range at 0.915 GHz, 2.45 GHz, 5.8 GHz, or 24.125 GHz which are IMS frequency bands that can be industrially applied. It is most preferable to have a dielectric loss coefficient in the above-mentioned range in the 2.45 GHz band, which is an inexpensive microwave frequency that is widely used for home use and industrial use. The supported palladium catalysts having a dielectric loss coefficient of 0.1 to 1.5 usually have a true density of 1.5 to 2.5 g / cm ³ and a relative dielectric constant of 2 to 7.

Here, the dielectric loss coefficient is a coefficient of the imaginary part of the complex dielectric constant represented by the following formula.
[Equation 1]
ε = ε'-ε''j
(Ε: complex dielectric constant, ε ′: relative dielectric constant, ε ″: dielectric loss coefficient)
Examples of the method for measuring the complex dielectric constant include a cavity resonator perturbation method, a coaxial probe reflection method, and a propagation delay method. In addition, for a powder sample, measurement accuracy and reproducibility can be improved by correcting the influence of voids by measuring the true density of the powder.

The production method of the present invention using the catalyst of the present invention has a general formula by irradiating microwaves in the presence of the catalyst of the present invention.
RX (I)
An aryl halide or aryl triflate represented by the general formula
R'B (OR ") ₂ (II)
Cross-coupling with an arylboronic acid derivative represented by general formula
RR '(III)
Can be efficiently produced.

  In the aryl halide or aryl triflate represented by the general formula (I), R is a monovalent aryl group, and the carbon number thereof is preferably 6 to 18, and more preferably 6 to 14. Specific examples of the aryl group include a phenyl group, a naphthyl group, and an anthryl group. Some of the hydrogen atoms of these aryl groups may be substituted with groups that do not participate in the reaction. Specific examples of these groups include alkyl groups, alkoxy groups, alkoxycarbonyl groups, acyl groups, cyano groups, nitro groups. Group, fluorine atom and the like.

  X represents a halogen atom or a trifluoromethanesulfonyloxy group selected from bromine, iodine and chlorine atoms. Thus, specific examples of aryl halides or aryl triflates having these groups include iodobenzene, bromobenzene, chlorobenzene, bromonaphthalene, bromoanthracene, 4-bromotoluene, 4-bromoanisole, ethyl 4-bromobenzoate, Examples include ethyl 4-chlorobenzoate, 4-bromoacetophenone, 4-chlorobenzonitrile, 1-chloro-4-nitrobenzene, 1-bromo-4-fluorobenzene, phenyl triflate and the like.

  On the other hand, in the aryl boronic acid derivative represented by the general formula (II), R ′ is a monovalent aryl group, and the carbon number thereof is preferably 6-18, and more preferably 6-14. Specific examples of R ′ include those exemplified as the specific examples of R above. R ″ may be a hydrogen atom or an alkyl group, and may be an alkylene group in which two R ″ are bonded at the ends to form a ring. Specific examples of such an alkylene group include trimethylene group and 1,1,2,2-tetramethylethylene group. Therefore, specific examples of arylboronic acid derivatives having these groups include phenylboronic acid, 4-formylphenylboronic acid, 4-hydroxyphenylboronic acid, 3-aminophenylboronic acid, 4-biphenylboronic acid, 10- Examples include bromoanthracene-9-boronic acid, pyrene-1-boronic acid, phenylboronic acid 1,3-propanediol ester, phenylboronic acid pinacol ester, 4-carboxyphenylboronic acid pinacol ester, and the like.

  The cross-coupling reaction between the aryl halide or aryl triflate represented by the general formula (I) and the aryl boronic acid derivative represented by the general formula (II) is usually performed in the presence of a base in order to promote the reaction. Perform the reaction. As the base, various bases including conventionally known ones such as inorganic and organic can be used. Specific examples thereof include sodium carbonate, potassium carbonate, cesium carbonate, sodium hydroxide, potassium hydroxide, potassium phosphate, tert-butoxy sodium, tert-butoxy potassium, triethylamine, tributylamine, 1,8-diazabicyclo [5. 4.0] -7-undecene and the like. Further, the molar ratio of the arylboronic acid derivative to the base relative to the aryl halide or aryl triflate can be arbitrarily selected. However, considering the yield of the biaryl compound relative to the aryl halide or aryl triflate, it is usually 0.5 or more and 3 It is as follows.

  The molar ratio of the catalyst of the present invention to the aryl halide or aryl triflate can be arbitrarily selected, but the molar ratio of palladium in the catalyst of the present invention to the aryl halide or aryl triflate is usually 0.0000001 to 0.00. 5.

  This coupling reaction can be performed in various types of conventionally known reaction apparatuses such as a batch type and a flow type. The reaction temperature is −20 ° C. or higher, preferably 0 to 250 ° C., more preferably 10 to 220 ° C. The reaction time depends on the reaction temperature, the amount of catalyst, the form of the reactor, etc., but is about 1 to 300 minutes, preferably about 1 to 240 minutes, more preferably about 1 to 180 minutes.

  The reaction can be carried out with or without a solvent, but when a solvent is used, hydrocarbons such as toluene and decalin (decahydronaphthalene), amides such as dimethylformamide, chlorobenzene, 1,2- or 1,3 -Various solvents other than those that react with the raw material, such as halogenated hydrocarbons such as dichlorobenzene, ethers such as anisole and dibutyl ether, can be used, and two or more types can be used in combination.

  In the production method of the present invention, microwave irradiation is performed by various commercially available devices equipped with a contact-type or non-contact-type temperature sensor, for example, a single mode type using a waveguide, or a multimode type similar to a home microwave oven. The microwave reactor etc. which have the following structure can be used. Specific examples of such commercially available devices are: Discover (CEM: microwave maximum output 300 W), Initiator (Biotage: microwave maximum output 400 W), MicroSYNCH (Milestone: microwave maximum output 1000 W), Green -Motif (made by IDX: microwave maximum output 300W), μReactor (manufactured by Shikoku Keiki Kogyo Co., Ltd .: microwave maximum output 800W) and the like. Also, the output of microwave irradiation, the type of cavity (multimode type, single mode type), irradiation mode (continuous, intermittent), presence or absence of forced cooling (cooling with air, inert gas, refrigerant, etc.), etc. , Can be arbitrarily determined according to the scale and type of reaction. The frequency of the microwave is usually 0.3 to 30 GHz, preferably 0.915 GHz, 2.45 GHz, 5.8 GHz, or 24.125 GHz, which are IMS frequency bands that can be industrially applied.

  A biaryl compound of the general formula (III) is produced by a coupling reaction in which microwave irradiation is performed. In this formula, examples of R and R ′ include those exemplified above. When the catalyst of the present invention is used in the production method of the present invention, for example, when an aryl bromide is used as a raw material, a yield of 70% or more is usually obtained. Is used in the production method of the present invention, a yield of 80% or more is obtained.

  The biaryl compound produced by the production method of the present invention can be purified by means usually used in organic chemistry such as distillation, recrystallization, column chromatography and the like.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to these Examples.

Example 1
Production of supported palladium catalyst (1):
In a Teflon reaction vessel with a Teflon screw cap, 10 g of a stirrer, poly (alkylene oxide) triblock copolymer (Pluronic P123, Sigma-Aldrich (average molecular weight 5800)), which is an organic template component, is added to 100 g of pure water. The dissolved solution and 21.25 g of tetraethoxysilane were added and stirred at room temperature for 30 minutes. To this solution, 71.5 g of concentrated hydrochloric acid was added, and 162.5 g of pure water was further added. The Teflon cap was tightened and sealed, stirred at room temperature for 30 minutes, and further stirred at 80 ° C. for 20 hours. The reaction mixture was added to 1 L of pure water, the white solid was filtered off, and the solid was washed with 2 L of pure water. The washed solid was dried overnight at 80 ° C. to obtain a porous silica precursor containing an organic template component as a white powder solid.

This white powdered solid (0.502 g) was calcined in a quartz tube electric furnace at 550 ° C. for 5 hours under a nitrogen stream (about 200 mL / min), and carbon-containing porous silica having an SBA-15 structure (C / SiO ₂ — 0.201 g of 1) was obtained as a gray powder solid.

2.01 mL of a solution obtained by dissolving 0.00011 g of palladium acetate in 10 mL of tetrahydrofuran was added to 0.201 g of C / SiO ₂ -1 obtained above, and the mixture was stirred at room temperature for 5 hours under nitrogen. This solution was concentrated under reduced pressure, and the remaining solid was dried in vacuum at 80 ° C. for 2 hours to obtain a catalyst (Pd / C / SiO ₂ −1) in which palladium was supported on carbon-containing porous silica having an SBA-15 structure. , Palladium loading 0.1%) was obtained as a gray powdery solid.

C / _SiO 2 -1 elemental analysis, nitrogen adsorption-desorption measurements, the true density measurements of Pd / C / _SiO 2 -1 (pycnometer method) and complex permittivity measurement (2.45 GHz cavity resonator perturbation method) was carried out The results were as follows.
<Measurement results>
Elemental analysis: carbon 0.43%; hydrogen 0.93%
Nitrogen adsorption / desorption measurement: specific surface area of BET method 883 m ² / g; BJH method center pore diameter 6.2 n
m
True density measurement: 1.83 g / cm ³
Complex permittivity measurement: relative permittivity 5.10; dielectric loss factor 0.997

Example 2
Production of supported palladium catalyst (2):
Except for changing the heating temperature in the quartz tube electric furnace from 550.degree. C. to 450.degree. C., as a result of performing the heating and baking and the treatment with the palladium acetate solution in the same manner as in Example 1, the porous silica precursor containing the organic template component From 0.507 g of white powdered solid, 0.205 g of carbon-containing porous silica having an SBA-15 structure as a gray powdered solid (C / SiO ₂ -2), and 0.205 g of C / SiO ₂ -2 Then, a catalyst (Pd / C / SiO ₂ -2, palladium supported amount 0.1%) in which palladium was supported on carbon-containing porous silica having an SBA-15 structure was obtained as a gray powdery solid.

Elemental analysis of C / SiO ₂ -2, nitrogen adsorption / desorption measurement, true density measurement (Pycnometer method) and complex permittivity measurement (2.45 GHz cavity resonator perturbation method) of Pd / C / SiO ₂ -2 The results were as follows.
<Measurement results>
Elemental analysis: carbon 1.35%; hydrogen 1.61%
Nitrogen adsorption / desorption measurement: BET method specific surface area 967 m ² / g; BJH method center pore diameter 7.1 n
m
True density measurement: 1.71 g / cm ³
Complex permittivity measurement: relative permittivity 5.43; dielectric loss factor 1.164

Example 3
Production of biaryl compounds:
Ethyl 4-bromobenzoate (Ia) 0.50 mmol, phenylboronic acid (IIa) 0.55 mmol, potassium carbonate (base) 1.0 mmol, Pd / C / SiO ₂ -1 (catalyst prepared in Example 1, ratio Dielectric constant 5.10, dielectric loss coefficient 0.997) 0.00005 mmol (mole number of palladium) and 1.0 ml N, N-dimethylformamide (solvent) were put in a reaction tube with a Teflon valve, and sealed under nitrogen. Then, with stirring, a microwave reaction device (Discoverer manufactured by CEM, 2.45 GHz, microwave maximum output 300 W) was irradiated with microwaves so that the temperature of the reaction solution reached a predetermined temperature (140 ° C.) in 2 minutes, It was maintained for 8 minutes. As a result of analyzing the product by gas chromatography, it was found that 4-ethoxycarbonylbiphenyl was produced in a yield of 64% (Table 1).

  In addition, the results of the reaction and analysis performed in the same manner as in Example 3 while changing the reaction conditions such as the catalyst and raw materials are shown in Table 1 (Examples 4 to 20).

  From the above table, by using a catalyst having a dielectric loss coefficient in the range of 0.1 to 3.0, the biaryl compound was obtained in a high yield of 70% or more in a reaction for 60 minutes using 4-bromobenzoic acid. Obtained. Further, by using a supported palladium catalyst having a dielectric loss coefficient in the range of 0.7 to 1.2 and having palladium supported on carbon-containing porous silica, a high yield of 80% or more can be obtained under the same reaction conditions. And the biaryl compound was obtained with little electric energy.

Comparative Example 1
Production of biaryl compounds:
In Example 5 of Table 1, instead of a supported palladium catalyst having a dielectric loss coefficient of 0.997, a commercially available supported palladium catalyst having a dielectric loss coefficient of> 3.0 showing the following measurement results (manufactured by N.E. As a result of the reaction between Ia and IIa using 5% palladium on carbon (containing 5% palladium and 54.2% water), the yield of IIIa was greatly reduced from 27% to 3%. Moreover, the average irradiation electric power in the comparative example 1 was 113W, and the electric energy required in order to obtain IIIa1mol was 113 kWh / mol.
True density measurement: 1.62 g / cm ³
Complex permittivity measurement: relative permittivity 50.9; dielectric loss factor> 3.0

  The result of Comparative Example 1 shows that when the dielectric loss coefficient of the supported palladium catalyst is larger than 3.0, the catalyst is heated too much by microwave irradiation, and the catalyst may be decomposed or deactivated. is there.

Comparative Example 2
Comparison with conventional methods:
In Examples 5, 8 and 9 in Table 1, instead of heating the supported palladium catalyst by irradiating microwaves, an aluminum block (Reference Example 1) or an oil bath (Reference Examples 2 and 3) was used. Table 2 shows the results of the reaction conducted under normal heating as reference examples.

  In any of the reference examples, the yield of the biaryl compound was lower than that of the corresponding example. This result shows that the normal heating reaction using an aluminum block or an oil bath does not provide as high catalytic activity as the reaction under microwave irradiation.

  The production method of the present invention provides a method by which a biaryl compound useful as a functional chemical can be produced efficiently and safely, and also provides a supported palladium catalyst used for this.

Therefore, the utility value of the present invention is high, and its industrial significance is great.

Claims (4)

Palladium is supported on porous silica and irradiated with microwaves in the presence of a supported palladium catalyst having a dielectric loss coefficient of 0.1 to 3.0, and the following general formula (I)
RX (I)
(In the formula, R represents a monovalent aryl group, X represents a halogen atom or trifluoromethanesulfonyloxy group selected from bromine, iodine and chlorine atoms. A group in which some of the hydrogen atoms of the aryl group do not participate in the reaction) Can be replaced with.)
An aryl halide or aryl triflate represented by the following general formula (II)
R'B (OR ") ₂ (II)
(In the formula, R ′ represents a monovalent aryl group, R ″ represents a hydrogen atom or an alkyl group. When two R ″ in the molecule are alkyl groups, they are bonded at the end to form a cyclic compound. It does not matter if it is.)
A cross-coupling reaction with an arylboronic acid derivative represented by the following general formula (III)
RR '(III)
(In the formula, R and R ′ have the same meaning as described above.)
In a method for producing a biaryl compound represented,
The porous silica is produced by firing a porous silica precursor containing an organic template component at a temperature of 400 ° C. or higher in an inert gas atmosphere, and contains 0.1 to 5% by mass of a carbon component. A method for producing the biaryl compound, which is carbon porous silica. How carbonaceous porous silica, to produce the SBA-15, FSM-22 or biaryl compound according to claim 1, wherein those having a basic structure of a MCM-41.   Carbon-containing porous silica containing 0.1 to 5% by mass of a carbon component produced by firing a porous silica precursor containing an organic template component at a temperature of 400 ° C. or higher in an inert gas atmosphere. A supported palladium catalyst for microwave reaction, wherein the supported catalyst has a dielectric loss coefficient of 0.1 to 3.0 after palladium is supported. The supported palladium catalyst for microwave reaction according to claim 3, wherein the carbon-containing porous silica has a basic structure of SBA-15, FSM-22 or MCM-41.