Palladium complex, coupling reaction catalyst, and method for producing aromatic compound

Abstract

To provide a palladium complex which can produce a target product with high activity in coupling reaction even under mild reaction conditions such as room temperature.SOLUTION: A palladium complex represented by the general formula (A) in the figure is used. (In the formula, X represents a chlorine atom or the like; R1 and R2 represent, e.g., a π-allyl structure or a ring structure formed by linking them; R3 and R4 each independently represent a C1-20 alkyl group or the like; and R5 and R6 each independently represent a C1-20 alkyl group or the like.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a novel palladium complex that can be used as a catalyst for coupling reactions. More specifically, the present invention relates to a palladium complex that can be suitably used as a catalyst for cross-coupling reactions such as the Suzuki-Miyaura reaction.

Background Art

[0002] In the field of organic synthetic chemistry including the synthesis of pharmaceuticals, chemical reactions that form carbon-carbon bonds are extremely important. As such a chemical reaction, a reaction that polarizes a carbon atom negatively by bonding a metal atom with a low electronegativity to the carbon atom, such as a Grignard reagent, and uses this as a nucleophile to form a carbon-carbon bond has been used for a long time. However, such Grignard reagents have problems such as a large management burden due to carcinogenicity and boiling point issues, and cannot be handled in the presence of water due to their high reactivity, requiring high caution during chemical synthesis.

[0003] Therefore, in recent years, among various coupling reactions, the Suzuki-Miyaura coupling reaction, which forms a carbon-carbon bond between an organoboron compound and an aryl halide, has attracted attention. For example, Patent Document 1 discloses that a carbon-carbon bond was formed by performing a Suzuki-Miyaura coupling reaction in a wet state between an aromatic boronic acid ester and an aromatic compound other than the aromatic boronic acid ester in the presence of a solid catalyst containing palladium.

[0004] Further, Patent Document 2 discloses that a palladium complex having di-tert-butyl(3-methyl-2-butenyl)phosphine as a ligand of palladium was used as a Suzuki-Miyaura coupling catalyst. Furthermore, Patent Document 3 discloses that a palladium complex having chloromethyl(tri-tert-butylphosphine) or the like as a ligand of palladium was used as a Suzuki-Miyaura coupling catalyst.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, various pharmaceutical and agricultural intermediates and organic electronic materials have been synthesized by coupling reactions. However, among the target substances, there are also compounds with low temperature stability. Those compounds with low temperature stability have problems such as a decrease in yield and the formation of by-products due to thermal decomposition or the like at reaction temperatures exceeding 100°C. As a result of intensive studies, the inventors have found that although complexes in which a phosphine having an alkenyl structure described in Patent Document 2 is coordinated to palladium multiple times exhibit excellent catalytic activity at a reaction temperature of around 130°C, they show substantially no activity in the temperature range near room temperature. In view of the above problems, an object of the present invention is to provide a palladium complex that has high activity in a coupling reaction and can obtain a target product even under mild reaction conditions such as room temperature.

Means for Solving the Problems

[0007] As a result of intensive studies, the inventors have found that the above problems can be solved by using a palladium complex having a specific structure in which a phosphine having an alkenyl structure is coordinated once, and thus have arrived at the present invention. That is, the gist of the present invention is as follows.

[0008] [1] A palladium complex represented by the following general formula (A).

Chemical Formula

[10] A method for producing a palladium complex represented by the general formula (A), comprising: a step of reacting a palladium compound represented by the following general formula (a) with a phosphine compound represented by the following general formula (b) to obtain a palladium complex, the method for producing a palladium complex.

Chemical formula

Chemical formula

[11] A method for producing an aromatic compound, comprising subjecting an aromatic boronic acid compound (B) or an aromatic boronic acid ester (B') and an aromatic compound (C) to a coupling reaction in the presence of the palladium complex according to any one of [1] to [8] to produce a carbon-carbon coupling reaction product (D).

[12] The production method according to

[11] , wherein the reaction temperature of the coupling reaction is 40°C or lower.

Advantages of the Invention

[0009] The palladium complex of the present invention can be used as a catalyst for a coupling reaction to produce a reaction product under mild conditions. In particular, when the palladium complex of the present invention is applied to the reaction between an aromatic compound having a halogen atom and a boron compound (Suzuki-Miyaura coupling), the target product can be produced under extremely mild conditions of room temperature and normal pressure. From these facts, the palladium complex of the present invention can not only reduce the production cost, but also be extremely effectively used in producing reaction products whose yields deteriorate at high temperatures. Therefore, the palladium complex of the present invention is particularly useful for producing information electronic materials and intermediates for medical and agricultural chemicals, and is extremely valuable industrially.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an example of a preferred embodiment for carrying out the present invention will be described. However, the following embodiments are illustrative for explaining the present invention, and the present invention is not limited to the following embodiments at all.

[0011] [Palladium complex] The palladium complex according to the present invention is represented by the following general formula (A). [Chemical formula]

[0012] In the above general formula (A), X represents a chlorine atom, a bromine atom, or an iodine atom. Among these, from the viewpoint of reactivity at low temperature, X is preferably a chlorine atom.

[0013] In the above general formula (A), R 1 and R 2 each independently represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, a cycloalkyl group having 5 to 10 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, or a heteroaryl group having 4 to 20 carbon atoms which may have a substituent, or R 1 represents a ring structure or a π-allyl ligand formed by linking with R 2 , but R 1 and R 2 do not have a phosphorus atom. In the above general formula (A), when R 1 and R 2 are each independent, it is preferable that they represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or an alkenyl group having 2 to 10 carbon atoms which may have a substituent. In the above general formula (A), R 1 and R 2When they are linked to form a ring structure, it preferably represents an alicyclic structure which may have a substituent, a heterocyclic structure which may have a substituent, or a π-allyl group which may have a substituent.

[0014] The alkyl group may be linear or branched. Examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, 2,2-dimethylpropyl group, n-hexyl group, 2-methylpentyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, and n-icosyl group. Among these, an alkyl group having 1 to 10 carbon atoms is preferable.

[0015] Examples of the alkenyl group having 2 to 10 carbon atoms include vinyl group, 1-propenyl group, 2-propenyl group, 1-butenyl group, 2-butenyl group, 3-methyl-2-butenyl group, 1-pentenyl group, 2-pentenyl group, 1-hexenyl group, 2-hexenyl group, 1-octenyl group. When R 1 , R 2 represents an alkenyl group having 2 to 10 carbon atoms, geometric isomers may exist. The geometric isomers may be either cis-isomer or trans-isomer, or both may coexist.

[0016] Examples of the cycloalkyl group having 5 to 10 carbon atoms include cyclopentyl group, cyclohexyl group, cycloheptyl group, and cyclooctyl group.

[0017] An aryl group is a group formed by the removal of one hydrogen atom bonded to the ring of an aromatic hydrocarbon. Examples of aryl groups having 6 to 20 carbon atoms include a phenyl group, 4-methylphenyl group, 2-methylphenyl group, 2,6-dimethylphenyl group, 1-naphthyl group, 2-naphthyl group, 3-phenanthryl group, and 2-anthryl group, etc. Examples of aryl groups having 6 to 20 carbon atoms which may have substituents include a phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,5-dimethylphenyl group, 2,4,6-trimethylphenyl group, 2,3,5,6-tetramethylphenyl group, 2-ethylphenyl group, 3,5-diethylphenyl group, 4-n-propylphenyl group, 4-isopropylphenyl group, 4-n-butylphenyl group, 4-tert-butylphenyl group, 1-naphthyl group, 2-naphthyl group, 2-biphenyl group, 3-biphenyl group, 4-biphenyl group, 2-fluoro-4-biphenyl group, 2-fluorenyl group, 9-phenanthrenyl group, 9-anthracenyl group, 1-pyrenyl group, 2-trifluoromethylphenyl group, 3-trifluoromethylphenyl group, 4-trifluoromethylphenyl group, 3,5-bis(trifluoromethyl)phenyl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 2,4-dimethoxyphenyl group, 2,5-dimethoxyphenyl group, 2,6-dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 3,5-dimethoxyphenyl group, 2-ethoxyphenyl group, 3-ethoxyphenyl group, 4-ethoxyphenyl group, 2-(benzyloxy)phenyl group, 2-phenoxyphenyl group, 4-phenoxyphenyl group, 2,3-methylenedioxyphenyl group, 3,4-methylenedioxyphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 2,4-difluorophenyl group, 2,5-difluorophenyl group, 2,6-difluorophenyl group, 3,4-difluorophenyl group, 3,5-difluorophenyl group, 2-formylphenyl group, 3-formylphenyl group, 4-formylphenyl group, 3-formyl-4-methoxyphenyl group, 2-cyanophenyl group, 3-cyanophenyl group, 4-cyanophenyl group, 2-acetylphenyl group, 3-acetylphenyl group, 4-acetylphenyl group, 3-carboxyphenyl group, 3-aminophenyl group, 2-(N,N-dimethylamino)phenyl group, 3-(N,N-dimethylamino)phenyl group, 4-(N,N-dimethylamino)phenyl group, and 2-(N,N-dimethylaminomethyl)phenyl group may be mentioned.,

[0018] The heteroaryl group is a group in which a carbon atom constituting the ring of the aryl group is substituted with a heteroatom or a carbonyl group., The heteroaryl group having 4 to 20 carbon atoms includes a monocyclic heteroaryl group, a condensed-ring heteroaryl group, a monovalent group formed by directly bonding or indirectly bonding two or more monocyclic and / or condensed-ring heteroaryl groups through a heteroatom (such as an oxygen atom, a nitrogen atom, a sulfur atom, etc.) or a carbonyl group (-CO-), and a monovalent group formed by directly bonding or indirectly bonding one or more monocyclic and / or condensed-ring heteroaryl groups and one or more monocyclic and / or condensed-ring aryl groups through a heteroatom (such as an oxygen atom, a nitrogen atom, a sulfur atom, etc.) or a carbonyl group (-CO-). The remaining bond of the nitrogen atom that indirectly bonds the heteroaryl groups is bonded to, for example, an alkyl group that may have a substituent, an aryl group that may have a substituent, etc. Note that the condensed ring contained in the condensed-ring heteroaryl group may be a condensed ring of two or more hetero rings or a condensed ring of one or more hetero rings and one or more aromatic rings.,

[0019] Examples of the heteroaryl group having 4 to 20 carbon atoms include groups represented by general formulas (ha1) to (ha7).

[0020] [Chemical formula] (In the formula, R represents a fluorine atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylcycloalkyl group, an arylalkenyl group, an arylalkynyl group, a heterocyclic group which may have an alkyl group, a group represented by -N(R’)2 (two R’s each independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a heterocyclic group which may have an alkyl group), a group represented by -Si(R’)3 (R’ has the same meaning as described above, and the three R’s may be the same or different), an acyl group, a group having a carbon atom-nitrogen atom double bond, an acid imide group, an alkoxycarbonyl group, a cycloalkoxycarbonyl group, an aryloxycarbonyl group, a carboxy group, a cyano group, a nitrile group, or a nitro group. Also, p represents an integer from 0 to 4. Also, Y represents a sulfur atom, an oxygen atom, or a group represented by -NR Y -. Also, R Y represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent. Also, ring A represents a heterocyclic ring or an aromatic ring. )

[0021] Examples of the groups represented by the general formulas (ha1) to (ha4) include the groups represented by the general formulas (ha1-1) to (ha4-12).

[0022]

Chemical formula

[0023]

Chemical formula

[0024] Among the heteroaryl groups having 4 to 20 carbon atoms which may have the substituents described above, 2-thienyl group, 3-methyl-2-thienyl group, 4-methyl-2-thienyl group, 5-methyl-2-thienyl group, 3,4-dimethyl-2-thienyl group, 3,5-dimethyl-2-thienyl group, 4,5-dimethyl-2-thienyl group, 3-thienyl group, 2-methyl-3-thienyl group, 4-methyl-3-thienyl group, 5-methyl-3-thienyl group, 2,4-dimethyl-3-thienyl group, 2,5-dimethyl-3-thienyl group, 4,5-dimethyl-3-thienyl group, 2-pyrrolyl group, 1-methyl-2-pyrrolyl group, 1-phenyl-2-pyrrolyl group, 3-pyrrolyl group, 1-methyl-3-pyrrolyl group, 1-phenyl-3-pyrrolyl group, 2-furyl group, 3-furyl group, 2-pyridyl group, 3-methyl-2-pyridyl group, 4-methyl-2-pyridyl group, 5-methyl-2-pyridyl group, 6-methyl-2-pyridyl group, 3-pyridyl group, 2-methyl-3-pyridyl group, 4-methyl-3-pyridyl group, 5-methyl-3-pyridyl group, 6-methyl-3-pyridyl group, 3-pyridazinyl group, 4-pyridazinyl group, 2-pyrimidyl group, 4-pyrimidyl group, 5-pyrimidyl group, 2-pyrazinyl group, 2-triazinyl group, 2-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group, 2-benzothienyl group, 7-benzothionyl group, 2-benzofuryl group, 7-benzofuryl group, 2-indolyl group, 1-methyl-2-indolyl group, 1-phenylindolyl group are preferred.

[0025] In the above general formula, when R is an alkoxy group, the alkoxy group may be linear or branched. The number of carbon atoms in the alkoxy group is usually 1 to 20. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, a 2,2-dimethylpropoxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy group, an n-tridecyloxy group, an n-tetradecyloxy group, an n-pentadecyloxy group, an n-hexadecyloxy group, an n-heptadecyloxy group, an n-octadecyloxy group, an n-nonadecyloxy group, and an n-icosyloxy group.

[0026] In the above general formula, when R is a cycloalkoxy group, the number of carbon atoms in the cycloalkoxy group is usually 3 to 20. Examples of the cycloalkoxy group include a cyclopropoxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, and a cyclooctyloxy group.

[0027] In the above general formula, when R is an alkylthio group, the number of carbon atoms in the alkylthio group is usually 1 to 20. Examples of the alkylthio group include a methylthio group, an ethylthio group, an n-propylthio group, an isopropylthio group, an n-butylthio group, an isobutylthio group, a sec-butylthio group, a tert-butylthio group, an n-pentylthio group, an n-hexylthio group, an n-heptylthio group, an n-octylthio group, a 2-ethylhexylthio group, an n-nonylthio group, an n-decylthio group, a 3,7-dimethyloctylthio group, and an n-dodecylthio group.

[0028] In the above general formula, when R is a cycloalkylthio group, the number of carbon atoms in the cycloalkylthio group is usually 3 to 20. Examples of the cycloalkylthio group include a cyclopropylthio group, a cyclopentylthio group, a cyclohexylthio group, a cycloheptylthio group, and a cyclooctylthio group.

[0029] In the above general formula, when R is an aryloxy group, the number of carbon atoms of the aryl group is usually 6 to 20. Examples of the aryloxy group include a phenoxy group, a naphthyloxy group, a phenanthryloxy group, and an anthryloxy group. The aryloxy group is a group in which an aryl group is bonded to an oxy group.

[0030] In the above general formula, when R is an arylthio group, the number of carbon atoms of the aryl group in the arylthio group is usually 6 to 20. Examples of the arylthio group include a phenylthio group and a naphthylthio group.

[0031] In the above general formula, when R is an arylalkyl group, the number of carbon atoms of the aryl group is usually 6 to 20, and the number of carbon atoms of the alkyl group is usually 1 to 20. The arylalkyl group is an alkyl group having an aryl group as a substituent.

[0032] In the above general formula, when R is an arylcycloalkyl group, the number of carbon atoms of the aryl group is usually 6 to 20, and the number of carbon atoms of the cycloalkyl group is usually 3 to 20. The arylcycloalkyl group is a cycloalkyl group having an aryl group as a substituent.

[0033] In the above general formula, when R is an arylalkenyl group, the number of carbon atoms of the aryl group is usually 6 to 20, and the number of carbon atoms of the alkenyl group is usually 2 to 8. Examples of the arylalkenyl group include a phenylalkenyl group and a naphthylalkenyl group. The arylalkenyl group is an alkenyl group having an aryl group as a substituent.

[0034] In the above general formula, when R is an alkynyl group, the number of carbon atoms in the alkynyl group is usually 2 to 8. Examples of the alkynyl group include an ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 1-pentynyl group, 2-pentynyl group, 1-hexynyl group, 2-hexynyl group, and 1-octynyl group.

[0035] In the above general formula, when R is an arylalkynyl group, the number of carbon atoms in the aryl group is usually 6 to 20, and the number of carbon atoms in the alkynyl group is usually 2 to 8. Examples of the arylalkynyl group include a phenylalkynyl group and a naphthylalkynyl group. Note that the arylalkynyl group is an alkynyl group having an aryl group as a substituent.

[0036] In the above general formula, when R is a heterocyclic group which may have an alkyl group as a substituent, the number of carbon atoms in the heterocyclic group is usually 3 to 20. Examples of the heterocyclic group include a thienyl group, pyrrolyl group, furyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, pyrrolidinyl group, piperidinyl group, quinolyl group, and isoquinolyl group. Note that the heterocyclic group is a remaining atomic group obtained by removing one hydrogen atom directly bonded to a carbon atom constituting the ring from a heterocyclic compound.

[0037] In the above general formula, when R is a group represented by -N(R')2, the two R's each independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a heterocyclic group which may have an alkyl group. Examples of the hydrocarbon group having 1 to 10 carbon atoms represented by R' include an alkyl group, cycloalkyl group, and aryl group. In the group represented by -N(R')2, it is preferable that at least one of the R's is a hydrocarbon group having 1 to 10 carbon atoms, or a heterocyclic group which may have an alkyl group. Examples of the group represented by -N(R’)2 include a methylamino group, a dimethylamino group, an ethylamino group, a diethylamino group, an n-propylamino group, a di-n-propylamino group, an isopropylamino group, a diisopropylamino group, an n-butylamino group, an isobutylamino group, a sec-butylamino group, a tert-butylamino group, an n-pentylamino group, an n-hexylamino group, an n-heptylamino group, an n-octylamino group, a 2-ethylhexylamino group, an n-nonylamino group, an n-decylamino group, a 3,7-dimethyloctylamino group, an n-dodecylamino group, a cyclopentylamino group, a dicyclopentylamino group, a cyclohexylamino group, a dicyclohexylamino group, a bis(trifluoromethyl)amino group, a phenylamino group, a diphenylamino group, a naphthylamino group, a pyridylamino group, a pyridazinylamino group, a pyrimidinylamino group, a pyrazinylamino group, and a triazinylamino group.

[0038] In the above general formula, when R is a group represented by -Si(R’)3, the three R’s may be the same or different, and at least one R’ is preferably a hydrocarbon group having 1 to 10 carbon atoms or a heterocyclic group which may have an alkyl group. Examples of the group represented by -Si(R’)3 include a trimethylsilyl group, a triethylsilyl group, a tri-n-propylsilyl group, a triisopropylsilyl group, a dimethylisopropylsilyl group, a diethylisopropylsilyl group, a tert-butyldimethylsilyl group, an n-pentyldimethylsilyl group, an n-hexyldimethylsilyl group, an n-heptyldimethylsilyl group, an n-octyldimethylsilyl group, a 2-ethylhexyldimethylsilyl group, an n-nonyldimethylsilyl group, an n-decyldimethylsilyl group, a 3,7-dimethyloctyldimethylsilyl group, a phenylalkylsilyl group, an alkoxyphenylalkylsilyl group, an alkylphenylalkylsilyl group, a naphthylalkylsilyl group, a phenylallyldimethylsilyl group, a triphenylsilyl group, a tri-p-xylylsilyl group, a tribenzylsilyl group, a diphenylmethylsilyl group, a tert-butyldiphenylsilyl group, and a dimethylphenylsilyl group.

[0039] In the above general formula, when R is an acyl group, the acyl group is a group represented by R’CO—, and R’ has the same meaning as described above. Examples of the acyl group include aliphatic acyl groups such as an acetyl group, a propionyl group, a butyryl group, and an isobutyryl group; and aromatic acyl groups such as a benzoyl group and a naphthoyl group.

[0040] In the above general formula, when R is a group having a carbon atom-nitrogen atom double bond, the group having a carbon atom-nitrogen atom double bond is a group formed by the elimination of one hydrogen atom directly bonded to the carbon atom or nitrogen atom constituting the carbon atom-nitrogen atom double bond in the imine compound. Examples of the imine compound include aldimine, ketimine, and a compound in which the nitrogen atom constituting the carbon atom-nitrogen atom double bond in aldimine has an alkyl group, an aryl group, an arylalkyl group, an arylalkenyl group, or an arylalkynyl group as a substituent.

[0041] Examples of the group having a carbon atom-nitrogen atom double bond include a group represented by -CR’’=N-R’’’ and a group represented by -N=C(R’’’)2 (wherein R’’ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, an arylalkenyl group, or an arylalkynyl group, and one or two R’’’s each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, an arylcycloalkyl group, an arylalkenyl group, or an arylalkynyl group. However, in the group represented by -N=C(R’’’)2, two R’’’s may be bonded to each other to form a divalent group (specifically, an alkylene group having 2 to 18 carbon atoms such as an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, or a hexamethylene group).). The number of carbon atoms of the group having a carbon atom-nitrogen atom double bond is usually 2 to 20, preferably 2 to 18, and more preferably 2 to 16.

[0042] Examples of the group having a carbon atom-nitrogen atom double bond include the groups shown below.

Chemical formula

[0043] When R in the above general formula is an acid imide group, the acid imide group is a group represented by (R’CO)2N-, where R’ has the same meaning as described above, and the two R’s may be the same or different. The two R’s may be bonded to each other to form a ring together with the carbon atom to which they are bonded and the nitrogen atom bonded to the carbon atom. The number of carbon atoms in the acid imide group is preferably 4 to 20, more preferably 4 to 18, and even more preferably 4 to 16.

[0044] Examples of the acid imide group include the groups shown below.

Chemical formula

[0045] When R in the above general formula is an alkoxycarbonyl group, the alkoxycarbonyl group is a group in which an alkoxy group is bonded to a carbonyl group. The alkoxy group has the same meaning as described above. Examples of the alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, isobutoxycarbonyl group, sec-butoxycarbonyl group, tert-butoxycarbonyl group, n-pentyloxycarbonyl group, n-hexyloxycarbonyl group, n-heptyloxycarbonyl group, n-octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, n-nonyloxycarbonyl group, n-decyloxycarbonyl group, 3,7-dimethyloctyloxycarbonyl group, n-dodecyloxycarbonyl group, trifluoromethoxycarbonyl group, pentafluoroethoxycarbonyl group, perfluorobutoxycarbonyl group, perfluorohexyloxycarbonyl group, and perfluorooctyloxycarbonyl group.

[0046] In the above general formula, when R is a cycloalkoxycarbonyl group, the cycloalkoxycarbonyl group is a group in which a cycloalkoxy group is bonded to a carbonyl group. The cycloalkoxy group has the same meaning as described above. Examples of the cycloalkoxycarbonyl group include a cyclohexyloxycarbonyl group.

[0047] In the above general formula, when R is an aryloxycarbonyl group, the aryloxycarbonyl group is a group in which an aryloxy group is bonded to a carbonyl group. The aryloxy group has the same meaning as described above. Examples of the aryloxycarbonyl group include a phenoxycarbonyl group, a naphthoxycarbonyl group, and a pyridyloxycarbonyl group.

[0048] Examples of the alicyclic structure include cycloalkyl structures having 1 to 10 carbon atoms such as a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, and a cyclooctane structure; an adamantane structure, a bicyclo[2.2.1]heptane structure, and tricyclo[5.2.1.0 2,6Examples of the bridged hydrocarbon structure include a decane structure and the like. Examples of the alicyclic structure which may have a substituent include a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a methylcyclobutane structure, a methylcyclopentane structure, a methylcyclohexane structure, a methylcycloheptane structure, a methylcyclooctane structure, an ethylcyclobutane structure, an ethylcyclopentane structure, an ethylcyclohexane structure, an ethylcycloheptane structure, an ethylcyclooctane structure, an n-propylcyclobutane structure, an n-propylcyclopentane structure, an n-propylcyclohexane structure, an n-propylcycloheptane structure, an isopropylcyclobutane structure, an isopropylcyclopentane structure, an isopropylcyclohexane structure, an isopropylcycloheptane structure, an n-butylcyclobutane structure, an n-butylcyclopentane structure, an n-butylcyclohexane structure, a tert-butylcyclobutane structure, a tert-butylcyclopentane structure, a tert-butylcyclohexane structure and other cycloalkyl structures having 1 to 10 carbon atoms which may have a substituent, an adamantane structure, a bicyclo[2.2.1]heptane structure, a tricyclo[5.2.1.0 2,6 Examples include a decane structure, a methylbicyclo[2.2.1]heptane structure, an ethylbicyclo[2.2.1]heptane structure, an n-propylbicyclo[2.2.1]heptane structure, and an isopropylbicyclo[2.2.1]heptane structure. Among these, a cycloalkyl structure having 1 to 10 carbon atoms which may have a substituent is preferred.

[0049] More specifically, examples of the heterocyclic structure include a structure represented by the following general formula (hc).

[0050] [Chemical formula] (In the formula, Y represents a sulfur atom, an oxygen atom, or a group represented by -NR Y -. Also, R Yrepresents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 20 carbon atoms which may have a substituent. Also, R 7 ~R 9 each independently represents an alkyl group having 1 to 6 carbon atoms which may be substituted with a fluorine atom, or an aryl group having 6 to 20 carbon atoms which may have a substituent.)

[0051] Since the definitions of the alkyl group having 1 to 20 carbon atoms which may have a substituent and the aryl group having 6 to 20 carbon atoms which may have a substituent are the same as above, the description is omitted.

[0052] The alkyl group having 1 to 6 carbon atoms which may be substituted with a fluorine atom is an alkyl group which may have a fluorine atom as a substituent. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a 2,2-dimethylpropyl group, an n-hexyl group, and a 2-methylpentyl group.

[0053] As the heterocyclic structure, from the viewpoint of reactivity at low temperature, a heterocyclic structure having 1 to 10 carbon atoms which may have a substituent is preferable, a heterocyclic structure represented by the following formulas (hc-1) to (hc-6) is more preferable, and an acetylacetonato group represented by the following formula (hc-1) is even more preferable.

[0054]

Chemical formula

[0055] The π-allyl structure refers to a structure in which an allyl ligand is η 3 coordinated, and more specifically, a structure represented by the following general formula (al) can be mentioned.

[0056]

Chemical formula

[0057] Since the definitions of the alkyl group having 1 to 6 carbon atoms which may have a substituent and the aryl group having 6 to 20 carbon atoms which may have a substituent are the same as above, the description is omitted.)

[0058] As the π-allyl structure, from the viewpoint of reactivity at low temperature, a π-allyl structure having 3 to 10 carbon atoms which may have a substituent is preferable, a π-allyl structure represented by the following formulas (al-1) to (al-5) is more preferable, and a cinnamyl group represented by the following formula (al-1), a crotyl group represented by the following formula (al-2), and an allyl group represented by the following formula (al-3) are more preferable.)

[0059]

Chemical formula

[0060] In the above general formula (A), R 3 and R 4 each independently represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, provided that R 3 and R 4 do not have a phosphorus atom.) Since the definitions of the alkyl group having 1 to 20 carbon atoms, the cycloalkyl group having 5 to 10 carbon atoms, and the aryl group having 6 to 20 carbon atoms are the same as above, the description is omitted.)

[0061] R 3 and R 4 from the viewpoint of reactivity at low temperature, an alkyl group having 1 to 10 carbon atoms is more preferable, an alkyl group having 1 to 4 carbon atoms is even more preferable, and a tert-butyl group is even more preferable.)

[0062] In the general formula (A) above, R 5 and R 6 each independently represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl group having 5 to 10 carbon atoms, provided that R 5 and R 6 do not simultaneously represent hydrogen atoms. Since the definitions of the alkyl group having 1 to 20 carbon atoms and the cycloalkyl group having 5 to 10 carbon atoms are the same as those above, the description thereof is omitted.

[0063] R 5 and R 6 are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms from the viewpoint of reactivity at low temperatures, more preferably that one is a hydrogen atom and the other is an alkyl group having 1 to 4 carbon atoms, or both are alkyl groups having 1 to 4 carbon atoms, and still more preferably that one is a hydrogen atom and the other is a methyl group, or both are methyl groups.

[0064] Preferred embodiments of the palladium complex of the present invention represented by the general formula (A) described above include, for example, the following. (1) A palladium complex representing a ring structure formed by the linkage of R 1 and R 2 ; (2) A palladium complex representing a heterocyclic structure having 1 to 10 carbon atoms which may have a substituent formed by the linkage of R 1 and R 2 ; (3) A palladium complex representing a heterocyclic structure represented by the above formulas (hc-1) to (hc-6) formed by the linkage of R 1 and R 2 ; (4) A palladium complex in which R 1 and R 2 are acetylacetonato groups; (5) A palladium complex representing a π-allyl structure formed by the linkage of R 1 and R 2 ; (6) R 1 and R 2A palladium complex having a π-allyl structure with 3 to 10 carbon atoms which may have a substituent formed by linking, (7)R 1 and R 2 is a cinnamyl group palladium complex, (8)R 1 and R 2 is a crotyl group palladium complex, (9)R 1 and R 2 is an allyl group palladium complex, (10)R 3 and R 4 is a palladium complex having an alkyl group with 1 to 20 carbon atoms, (11)R 3 and R 4 is a palladium complex having an alkyl group with 1 to 10 carbon atoms, (12)R 3 and R 4 is a palladium complex having an alkyl group with 1 to 4 carbon atoms, (13)R 3 and R 4 is a tert-butyl group palladium complex, (14)R 5 and R 6 One of them is a hydrogen atom and the other is a palladium complex having an alkyl group with 1 to 4 carbon atoms, (15)R 5 and R 6 One of them is a hydrogen atom and the other is a methyl group palladium complex, (16)R 5 and R 6 is a palladium complex having an alkyl group with 1 to 4 carbon atoms, (17)R 5 and R 6 is a methyl group palladium complex, (18)R 3 and R 4 is a tert-butyl group, and R 5 and R 6 One of them is a hydrogen atom and the other is a methyl group palladium complex, (19)R 3 and R 4is a tert-butyl group, R 5 and R 6 is a palladium complex in which is a methyl group, (20) a palladium complex in which X is a chlorine atom, are mentioned, but are not limited thereto.

[0065] More preferred embodiments of the palladium complex of the present invention specifically include chloro(acetylacetonato)(di-tert-butylcrotylphosphine)palladium, chloro(acetylacetonato)(di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium, chloro(1,1,5,5-tetrafluoro-2,4-pentanedionato)(di-tert-butylcrotylphosphine)palladium, chloro(1,1,5,5-tetrafluoro-2,4-pentanedionato)(di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium, chloro(hexafluoroacetylacetonato)(di-tert-butylcrotylphosphine)palladium, chloro(hexafluoroacetylacetonato)(di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium, chloro(trifluoro-2,4-pentanedionato)(di-tert-butylcrotylphosphine)palladium, chloro(trifluoro-2,4-pentanedionato)(di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium, chloro(2,6-dimethyl-3,5-heptanedionato)(di-tert-butylcrotylphosphine)palladium, chloro(2,6-dimethyl-3,5-heptanedionato)(di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium, chloro(6-methyl-2,4-heptanedionato)(di-tert-butylcrotylphosphine)palladium, chloro(6-methyl-2,(Di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium(4-heptanedionato), palladium(chloro)(crotyl)(di-tert-butylcrotylphosphine), palladium(chloro)(crotyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine), palladium(chloro)(allyl)(di-tert-butylcrotylphosphine), palladium(chloro)(allyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine), palladium(chloro)(2-methylallyl)(di-tert-butylcrotylphosphine), palladium(chloro)(2-methylallyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine), palladium(chloro)(cinnamyl)(di-tert-butylcrotylphosphine), palladium(chloro)(cinnamyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine), palladium(chloro)(4-methylphenylallyl)(di-tert-butylcrotylphosphine), palladium(chloro)(4-methylphenylallyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine), palladium(chloro)(4-isopropylphenylallyl)(di-tert-butylcrotylphosphine), palladium(chloro)(4-isopropylphenylallyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine) are included.,

[0066] Among these, chloro(acetylacetonato)(di-tert-butylcrotylphosphine)palladium, chloro(crotyl)(di-tert-butylcrotylphosphine)palladium, chloro(crotyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium, chloro(allyl)(di-tert-butylcrotylphosphine)palladium, and chloro(cinnamyl)(di-tert-butylcrotylphosphine)palladium are preferred, and chloro(acetylacetonato)(di-tert-butylcrotylphosphine)palladium, chloro(crotyl)(di-tert-butylcrotylphosphine)palladium, chloro(crotyl)(di-tert-butyl(3-methyl-2-butenyl)phosphine)palladium, and chloro(cinnamyl)(di-tert-butylcrotylphosphine)palladium are more preferred.

[0067] [Method for Producing Palladium Complex] The method for producing the palladium complex of the present invention conforms to the method described in J. Org. Chem., 2011, 76, pp7918 - 7932. More specifically, it includes a step of reacting a palladium compound represented by the general formula (a) with a phosphine compound represented by the following general formula (b) to obtain a palladium complex.

[0068] [Chemical Formula] (R in the formula 1 and R 2 are as defined above, so the description is omitted.)

[0069] [Chemical Formula] (R in the formula 3 ~R 6 are as defined above, so the description is omitted.)

[0070] The reaction to obtain the palladium complex can be carried out by heating and stirring, as necessary, a palladium compound represented by the general formula (a), a phosphine compound represented by the general formula (b), and a solvent such as tetrahydrofuran (hereinafter referred to as "THF").

[0071] As the stirring conditions, the stirring time is usually 30 minutes to 3 hours. The stirring temperature is usually 20 to 50 °C. Stirring may be carried out under an air atmosphere or under an inert atmosphere such as nitrogen or argon. After stirring, the palladium complex can be isolated by distilling off the solvent.

[0072] The addition amount of the phosphine compound represented by the general formula (b) is usually 2.0 to 2.2 mol with respect to 1 mol of the palladium compound represented by the general formula (a). Also, the amount of the solvent used is usually 1 to 10 ml with respect to 1 g of the palladium compound represented by the general formula (a).

[0073] [Coupling reaction catalyst] The coupling reaction catalyst of the present invention consists of the above-described palladium complex. The reason why the coupling reaction catalyst consisting of the palladium complex of the present invention exhibits reaction activity at a low temperature of about room temperature is not clear, but under the catalytic reaction conditions, the reduction reaction from divalent palladium species to zero-valent palladium species is promoted by the phosphine having an alkenyl structure coordinated to palladium, It is presumed that this is because it has become easy to generate a palladium(0) phosphine species having high activity for the coupling reaction. Among them, by using an acetylacetonato group, a cinnamyl group, a crotyl group, or an allyl group, it is considered that a palladium(0) phosphine species is preferably generated and the reaction is facilitated.

[0074] As an example of using the above-described palladium complex as a coupling reaction catalyst, in addition to the Suzuki-Miyaura coupling reaction described later, it can be used in the following similar coupling reactions and chemical reactions. (a) Stille cross-coupling of an organotin compound with a carbon electrophile having a halogen or pseudohalogen as a leaving group; (b) Hiyama cross-coupling of an organosilane with an aryl, heteroaryl, or vinyl halide or pseudohalide; (c) Negishi cross-coupling of an organozinc compound with an aryl, heteroaryl, or vinyl halide or pseudohalide; (d) Kumada cross-coupling of a Grignard compound with an aryl, heteroaryl, or vinyl halide or pseudohalide; (e) Sonogashira cross-coupling of a terminal alkyne with an aryl, heteroaryl, or vinyl halide or pseudohalide; (f) α-arylation of an enolate and other stabilized carbanions with an aryl or heteroaryl halide or pseudohalide; (g) Cyanation of an aryl or heteroaryl halide or pseudohalide; (h) Carbonylation of an aryl or heteroaryl halide or pseudohalide; (i) Heck-coupling of an aryl, heteroaryl, or vinyl halide or pseudohalide to an olefin.

[0075] [Method for producing aromatic compounds] The method for producing an aromatic compound of the present invention is a method for producing a carbon-carbon coupling reaction product (D) by subjecting an aromatic boronic acid compound (B) or an aromatic boronic acid ester (B') and an aromatic compound (C) to a coupling reaction in the presence of the above-described palladium complex. The method for producing an aromatic compound of the present invention is a Suzuki-Miyaura coupling reaction for producing an aromatic compound by forming a carbon-carbon bond from an aromatic boronic acid compound (B) or an aromatic boronic acid ester (B') and an aromatic compound (C).

[0076] In the method for producing an aromatic compound of the present invention, the target product can be produced under extremely mild conditions such as room temperature and normal pressure. Therefore, the method for producing an aromatic compound of the present invention is useful in the manufacturing processes of information and electronic materials and pharmaceutical and agricultural chemical intermediates, and is extremely valuable industrially.

[0077] The aromatic boronic acid compound (B) refers to a compound containing an aromatic ring and a boronic acid group in the molecule. Examples of the aromatic boronic acid compound (B) include acetylbenzene boronic acid, aminobenzene boronic acid, benzene boronic acid, benzenediboronic acid, benzyloxybenzene boronic acid, biphenyl boronic acid, biphenyldiboronic acid, (trifluoromethoxy)benzene boronic acid, (trifluoromethyl)benzene boronic acid, bis(trifluoromethyl)benzene boronic acid, carboxybenzene boronic acid, carboxyethylbenzene boronic acid, (carboxyvinyl)benzene boronic acid, cyanobenzene boronic acid, methoxybenzene boronic acid, dimethoxybenzene boronic acid, trimethoxybenzene boronic acid, methylbenzene boronic acid, dimethylbenzene boronic acid, ethylbenzene boronic acid, propylbenzene boronic acid, butylbenzene boronic acid, pentylbenzene boronic acid, nonylbenzene boronic acid, (methanesulfinyl)benzene boronic acid, (methanesulfonyl)benzene boronic acid, (ethanesulfonyl)benzene boronic acid, (methylthio)benzene boronic acid, (ethylthio)benzene boronic acid, formylbenzene boronic acid, formyl-methoxybenzene boronic acid, hydroxybenzene boronic acid, (hydroxymethyl)benzene boronic acid cyclic monoester, (hydroxymethyl)benzene boronic acid, vinylbenzene boronic acid, (methoxycarbonyl)benzene boronic acid, nitrobenzene boronic acid, (nitrovinyl)benzene boronic acid, isopropyl-methoxybenzene boronic acid, (methylenedioxy)benzene boronic acid, naphthalene boronic acid, and methoxynaphthalene boronic acid.

[0078] The aromatic boronic acid ester (B’) refers to a compound containing an aromatic ring and a boronic acid ester group in the molecule. Examples of the aromatic boronic acid ester (B’) include those that form an ester structure with one or two of the boronic acid groups of the aromatic boronic acid compound (B). Further, the ester structure may be such that the same molecule forms an ester structure together with two hydroxyl groups of the boronic acid group to form a ring structure containing two oxygen atoms. Examples of the aromatic boronic acid ester (B’) include 5,5-dimethyl-2-phenyl-1,3,2-dioxaborolane, 5,5-dimethyl-2-(4-fluorophenyl)-1,3,2-dioxaborolane, methyl 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate, dimethyl 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzene-1,3-dicarboxylate, 4,4,5,5-tetramethyl-2-(2-azulenyl)-1,3,2-dioxaborolane, and 5,5-dimethyl-2-(2,4,6-trimethylphenyl)-1,3,2-dioxaborolane.

[0079] In addition, the aromatic ring of the aromatic boronic acid compound (B) or the aromatic boronic acid ester (B’) may optionally have a substituent. Examples of the substituent include an alkyl group (e.g., an alkyl group having 1 to 10 carbon atoms), an alkenyl group (e.g., an alkenyl group having 2 to 10 carbon atoms), an alkynyl group (e.g., an alkynyl group having 2 to 10 carbon atoms), an alkoxy group (e.g., an alkoxy group having 1 to 10 carbon atoms), a hydroxyl group, an amino group, a mono- or dialkylamino group, a carboxyl group, an alkoxycarbonyl group (e.g., an alkoxycarbonyl group having 1 to 10 carbon atoms), a cyano group, a nitro group, a silicon-containing group (e.g., a trialkylsilyl group), an acyl group (e.g., an acetyl group, a formyl group), an aminocarbonyl group, an aryl group (e.g., a phenyl group), a heteroaryl group (e.g., a pyridyl group, a pyrrolyl group, a furyl group), a phosphorus atom-containing group (e.g., a dialkylphosphino group, a diarylphosphino group, a dialkylphosphoryl group, a diarylphosphoryl group, a dialkoxyphosphoryl group, a diaryloxyphosphoryl group), and a sulfur atom-containing group (e.g., a thienyl group, a sulfo group, a sulfino group, a sulfeno group). The aromatic ring may have 1 to 3 substituents selected from the exemplified substituents.

[0080] The aromatic compound (C) refers to an aromatic compound other than the aromatic boronic acid compound (B) or the aromatic boronic acid ester (B’), which can be used in the production of a carbon-carbon coupling reaction product with the aromatic boronic acid compound (B) or the aromatic boronic acid ester (B’). Examples of the aromatic compound (C) include halogenated aromatic compounds such as 1-bromo-4-nitrobenzene, p-bromoanisole, o-bromotoluene, 1-bromo-2,4,6-trimethylbenzene, 4-bromo-2,6-dichlorophenol, 2-bromobenzonitrile, and 4,7-dibromo-2-alkyl-2H-benzotriazole.

[0081] In addition, the aromatic ring of the aromatic compound (C) may optionally have a substituent. Examples of the substituent include an alkyl group (e.g., an alkyl group having 1 to 10 carbon atoms), an alkenyl group (e.g., an alkenyl group having 2 to 10 carbon atoms), an alkynyl group (e.g., an alkynyl group having 2 to 10 carbon atoms), an alkoxy group (e.g., an alkoxy group having 1 to 10 carbon atoms), a hydroxyl group, an amino group, a mono- or dialkylamino group, a carboxyl group, an alkoxycarbonyl group (e.g., an alkoxycarbonyl group having 1 to 10 carbon atoms), a cyano group, a nitro group, a silicon-containing group (e.g., a trialkylsilyl group), an acyl group (e.g., an acetyl group, a formyl group), an aminocarbonyl group, an aryl group (e.g., a phenyl group), a heteroaryl group (e.g., a pyridyl group, a pyrrolyl group, a furyl group), a phosphorus atom-containing group (e.g., a dialkylphosphino group, a diarylphosphino group, a dialkylphosphoryl group, a diarylphosphoryl group, a dialkoxyphosphoryl group, a diaryloxyphosphoryl group), and a sulfur atom-containing group (e.g., a thienyl group, a sulfo group, a sulfino group, a sulfeno group). The aromatic ring may have 1 to 3 substituents selected from the exemplified substituents.

[0082] Further, in the method for producing the aromatic compound of the present invention, a coupling reaction may be carried out in the coexistence of a base. As the base that may coexist in the method for producing the aromatic compound of the present invention, an organic base or an inorganic base can be appropriately used.

[0083] Examples of the organic base include amines such as triethylamine, pyridine, aniline, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,4-diazabicyclo[2.2.2]octane, and 1,8-diazabicyclo[5.4.0]-7-undecene. Examples of the inorganic base include hydroxides, fluorides, carbonate compounds, bicarbonate compounds, or phosphate compounds of alkali metals (such as lithium, sodium, potassium, rubidium, cesium, etc.) or alkaline earth metals (such as beryllium, magnesium, calcium, strontium, barium, etc.). More specifically, sodium carbonate, potassium carbonate, tripotassium phosphate, trisodium phosphate, sodium bicarbonate, and sodium metaborate, etc. may be mentioned. The bases exemplified above may be used alone or in combination of two or more.

[0084] Also, the addition amount of the base can be used in the range of 0.1 to 10 moles, and may be in the range of 0.5 to 3 moles, relative to 1 mole of the aromatic compound (C) which is one of the reactants.

[0085] In addition, in the method for producing the aromatic compound of the present invention, as other optional components, the coupling reaction may be appropriately carried out in the presence of an inorganic salt such as sodium chloride.

[0086] Moreover, the method for producing the aromatic compound of the present invention is not particularly limited, but a coupling reaction using a known solid-phase catalyst can be appropriately used. In the method for producing the aromatic compound of the present invention, it is preferable to use the Suzuki-Miyaura coupling. By using the method for producing the carbon-carbon coupling product, separation of the solid catalyst and the product during or after the reaction becomes easy even in the Suzuki-Miyaura coupling, etc.

[0087] The ratio of the amounts of use of the aromatic boronic acid compound (B) or the aromatic boronic acid ester (B') and the aromatic compound (C) can be 0.5 to 10:1 in molar ratio, and may be in the range of 0.8 to 2:1, i.e., [aromatic boronic acid compound (B) or the above aromatic boronic acid ester (B')]:[aromatic compound (C)].

[0088] In addition, the solvent used in the method for producing an aromatic compound of the present invention is not particularly limited. For example, methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n - hexane, diethyl ether, diisopropyl ether, n - butyl methyl ether, t - butyl methyl ether, benzene, toluene, xylene, cumene, cymene, mesitylene, diisopropylbenzene, pyridine, pyrimidine, pyrazine, pyridazine, methanol, ethanol, n - propyl alcohol, isopropyl alcohol, butanol, aminoethanol, N,N - dimethylaminoethanol, chloroform, dichloromethane, carbon tetrachloride, dichloroethane, trichloroethane, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N - methyl - 2 - pyrrolidone (NMP), dimethoxyethane (DME), and water can be mentioned. Among them, preferably, water; alcohols having 1 to 6 carbon atoms such as methanol, ethanol, and isopropyl alcohol; aromatic hydrocarbons such as toluene; polar organic solvents such as 1,4 - dioxane; or combinations thereof can be mentioned. Among these, a mixed solvent of toluene and water is more preferable. When using a mixed solvent of toluene and water, the volume ratio of toluene to water is preferably in the range of 1:9 to 9:1.

[0089] In addition, in the method for producing an aromatic compound of the present invention, the addition amount of the palladium complex used can be in the range of 0.001 to 20 mol% as palladium with respect to the aromatic compound (C) which is one of the reactants, and may be in the range of 0.01 to 10 mol%, or may be in the range of 0.05 to 5 mol%.

[0090] In addition, in the method for producing an aromatic compound of the present invention, the coupling reaction can be carried out, for example, in an air atmosphere or in an atmosphere of an inert gas such as nitrogen or argon, but is preferably carried out in an inert gas atmosphere.

[0091] The reaction temperature of the coupling reaction is preferably 40°C or lower, more preferably 20 - 40°C, and even more preferably room temperature - 40°C. Also, the reaction time can be arbitrarily set within 0.1 - 48 hours.

[0092] By using the palladium complex of the present invention as the coupling reaction catalyst as described above, even under mild reaction conditions, the coupling reaction proceeds in a short time, and the target product can be obtained.

Examples

[0093] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0094] <Raw material: Palladium complex> (Production Example A-1: Chloro(acetylacetonato)(di-t-butylcrotylphosphine)palladium(II): [PdCl(acac)(Crophos)]) 3.6 g of bis(acetylacetonato)palladium complex and 15 mL of tetrahydrofuran were added to a 100 mL eggplant-shaped flask that had been sufficiently purged with nitrogen. 2.5 g of di-t-butylcrotylphosphine was added thereto, and the mixture was stirred for 60 minutes. Next, 3 mL of 4M HCl dioxane solution was added, and the mixture was stirred for 2 hours. The solvent was distilled off using an evaporator, and the residue was washed with 10 mL of hexane. The obtained solid was dried to obtain the target chloro(acetylacetonato)(di-t-butylcrotylphosphine)palladium(II). The structure of the obtained palladium complex is shown below. The production ratio (yield) of the product with respect to the palladium raw material was 95%.

[0095]

Chemical formula

[0096] (Production Example A-2: Chloro(crotyl)(di-t-butylcrotylphosphine)palladium(II): [PdCl(crotyl)(crophos)]) In a triangular flask thoroughly purged with nitrogen, 0.97 g of di-μ-chlorobis[(η-crotyl)palladium(II)], 2 mL of tetrahydrofuran, and 1.0 g of di-t-butylcrotylphosphine were added at room temperature and stirred for 60 minutes. The solvent was distilled off using an evaporator and washed with 10 mL of hexane. The resulting precipitate was dried in a desiccator, 1 1H NMR and 31 As a result of evaluation by 31P NMR, the target chloro(crotyl)(di-t-butylcrotylphosphine)palladium(II) was obtained. The structure of the obtained palladium complex is shown below. The production ratio (yield) of the product with respect to the palladium raw material was 70%. 1 1H NMR (400 MHz, CDCl3) peak positions: 5.76 (1H, m), 5.56 (1H, m), 5.12 (1H, m), 4.38 (1H, m), 3.57 (1H, m), 2.93 (2H, m), 2.48 (1H, d, J = 11.6 Hz), 1.80 (3H, dd, J = 8.4 Hz, 6.4 Hz), 1.68 (3H, m), 1.30 (18H, m). 31 31P NMR (162 Hz, CDCl3) peak positions: 59.8, 57.3.

[0097]

Chemical formula

[0098] (Production Example A-3: Chloro(allyl)(di-t-butylcrotylphosphine)palladium(II): [PdCl(C3H5)(crophos)]) In a triangular flask thoroughly purged with nitrogen, 9.1 g of di-μ-chlorobis[(η-allyl)palladium(II)], 20 mL of tetrahydrofuran, and 10.0 g of di-t-butylcrotylphosphine were added at room temperature and stirred overnight. The solvent was distilled off using an evaporator and washed with 20 mL of hexane. The resulting precipitate was dried in a desiccator to obtain the target chloro(allyl)(di-t-butylcrotylphosphine)palladium(II). The structure of the obtained palladium complex and, 1 1H NMR and 31The evaluation results of ³¹P NMR are shown below. The production ratio (yield) of the product with respect to the palladium raw material was 54%. 1 ¹H NMR (400 MHz, CDCl₃) peak positions: 5.73 (1H, m), 5.55 (1H, m), 5.40 (1H, m), 4.72 (1H, m), 3.81 (1H, m), 3.69 (1H, m), 2.90 (2H, m), 2.67 (1H, d, J = 12.0 Hz), 1.68 (3H, m), 1.32 (18H, m). 31 ³¹P NMR (162 Hz, CDCl₃) peak positions: 57.4, 55.2.

[0099]

Chemical formula

[0100] (Production Example A-4: Chloro(cinnamyl)(di-t-butylcrotylphosphine)palladium(II): [PdCl(cinnamyl)(crophos)]) To a three-necked flask sufficiently purged with nitrogen, 1.3 g of di-μ-chlorobis[(η-cinnamyl)palladium(II)], 2 mL of tetrahydrofuran, and 1.0 g of di-t-butylcrotylphosphine were added at room temperature and stirred overnight. The solvent was distilled off using an evaporator and washed with 10 mL of hexane. The obtained precipitate was dried in a desiccator to obtain the target chloro(cinnamyl)(di-t-butylcrotylphosphine)palladium(II). The structure of the obtained palladium complex and 1 ¹H NMR and 31 the evaluation results of ³¹P NMR are shown below. The production ratio (yield) of the product with respect to the palladium raw material was 58%. 1 ¹H NMR (400 MHz, CDCl₃) peak positions: 7.51 (2H, m), 7.35 (3H, m), 5.79 (2H, m), 5.57 (1H, m), 5.23 (1H, dd, J = 13.2 Hz, J = 9.6 Hz), 3.74 (1H, m), 2.92 (2H, m), 2.72 (1H, d, J = 11.6 Hz), 1.69 (3H, m), 1.30 (18H, d, J = 12.4 Hz). 31 1P NMR (162 Hz, CDCl3) peak positions: 62.1, 59.6.

[0101]

Chemical formula

[0102] (Production Example A-5: Chloro(crotyl)(di-t-butyl(3-methyl-2-butenyl)phosphine)palladium(II): [PdCl(crotyl)(m-crophos)]) To a three-necked flask sufficiently purged with nitrogen, 0.9 g of di-μ-chlorobis[(η-crotyl)palladium(II)], 2 mL of tetrahydrofuran, and 1.0 g of di-t-butyl(3-methyl-2-butenyl)phosphine were added at room temperature and stirred overnight. The solvent was distilled off using an evaporator and washed with 10 mL of hexane. The resulting precipitate was dried in a desiccator to obtain the target chloro(crotyl)(di-t-butyl(3-methyl-2-butenyl)phosphine)palladium(II). The structure of the obtained palladium complex and 1 1H NMR and 31 the evaluation results of 31P NMR are shown below. The production ratio (yield) of the product relative to the palladium raw material was 74%. 1 1H NMR (400 MHz, CDCl3) peak positions: 5.43 (1H, m), 5.13 (1H, m), 4.38 (1H, m), 3.51 (1H, d, J = 2.0 Hz), 2.86 (2H, m), 2.47 (1H, d, 11.6 Hz), 1.80 (3H, dd, J = 8.4 Hz, J = 6.4 Hz), 1.72 (3H, s), 1.67 (3H, s), 1.30 (18H, dd, J = 13.2 Hz, J = 2.0 Hz). 31 31P NMR (162 Hz, CDCl3): 59.4.

[0103]

Chemical formula

[0104] (B-1: Dichlorobis(di-t-butylcrotylphosphine)palladium(II): [PdCl2(Crophos)2]) It is manufactured by N.E. Chemcat Corporation, and the product name is NECO-295. The structure is shown below.

[0105]

Chemical formula

[0106] (B-2: Dichlorobis(di-t-butyl(3-methyl-2-butenyl)phosphine)palladium(II): [PdCl2(m-Crophos)2]) It is manufactured by N.E. Chemcat, and the product name is NECO-296. The structure is shown below.

Chemical formula

[0107] (B-3: Dichlorobis(tricyclohexylphosphine)palladium(II): [PdCl2(PCy3)2]) It is manufactured by N.E. Chemcat Corporation, and the product name is "[PdCl2(PCy3)2]". The structure is shown below.

Chemical formula

[0108] (B-4: Chlorophenylallyl[1,3-bis(diisopropylphenyl)-2-imidazolidinylidene]palladium(II): [PdCl(cinnamyl)(SIpr)] It is manufactured by Umicore, and the product name is CX-32. The structure is shown below.

Chemical formula

[0109] (Production Example B-5: Chloro(allyl)(2-dicyclohexylphosphino-2’,6’-diisopropoxy-1,1’-biphenyl)palladium(II): [PdCl(C3H5)(Ruphos)]) To a three-necked flask sufficiently purged with nitrogen, 0.86 g (4.7 mmol) of di-μ-chlorobis[(η-allyl)palladium(II)], 2.2 g (4.7 mmol) of 2-dicyclohexylphosphino-2’,6’-diisopropoxybiphenyl (RuPhos), and 4 mL of tetrahydrofuran were added at room temperature and stirred overnight. After adding 20 mL of hexane, the resulting precipitate was filtered off and washed with 10 mL of hexane to obtain the target chloro(allyl)(2-dicyclohexylphosphino-2’,6’-diisopropoxy-1,1’-biphenyl)palladium(II) as a yellow powder. The structure of the obtained palladium complex is shown below. The production ratio (yield) of the product with respect to the palladium raw material was 77%.

[0110] [Chemical Formula]

[0111] <Reaction: Method for Producing Aromatic Compounds> <Example 1> One equivalent of 4-bromoanisole, 1.1 equivalents of phenylboronic acid, 0.001 equivalents of Pd complex (A-1), and 1.2 equivalents of tripotassium phosphate were mixed in a toluene / water mixed solvent (volume ratio 9:1) and stirred at room temperature for 1 hour. The resulting reaction mixture was quantified using gas chromatography. The yield of the obtained target product, 4-methoxybiphenyl, was 95% based on the raw material (4-bromoanisole standard).

[0112] <Examples 2 to 5, Comparative Examples 1 to 5> Evaluation was carried out in the same manner as in Example 1 except that the Pd complex (A-1) was changed as shown in Table 1. The yields of the target products obtained in each example and comparative example are shown in Table 1.

[0113] [Table 1]

[0114] As can be seen from Table 1, when the palladium complex (coupling reaction catalyst) of the present invention is used, it can be seen that the coupling reaction proceeds in a short time of 1 hour even under mild reaction conditions of room temperature. Therefore, the palladium complex (coupling reaction catalyst) of the present invention is useful for the production of information electronic materials and pharmaceutical and agricultural chemical intermediates, and can be said to be extremely valuable industrially.

Claims

1. A palladium complex represented by the following general formula (A). 【Chemical Formula 1】 (In the formula, X represents a chlorine atom, a bromine atom, or an iodine atom, R １ , R ２ each independently represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, a cycloalkyl group having 5 to 10 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, or a heteroaryl group having 4 to 20 carbon atoms which may have a substituent, or R １ represents a ring structure or a π-allyl structure formed by linking with R ２ , R ３ and R ４ represent a tert-butyl group, R ５ , R ６ each independently represents a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl group having 5 to 10 carbon atoms, but The substituents that the alkyl group, alkenyl group, cycloalkyl group, aryl group, and heteroaryl group may have are a fluorine atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylcycloalkyl group, an arylalkenyl group, an arylalkynyl group, a heterocyclic group which may have an alkyl group, a group represented by -N(R') ２ (In the formula, two R's each independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a heterocyclic group which may have an alkyl group.), -Si(R') ３A group represented by (wherein R' has the same meaning as described above, and the three R's may be the same or different), an acyl group, a group having a carbon atom-nitrogen atom double bond, an acid imide group, an alkoxycarbonyl group, a cycloalkoxycarbonyl group, an aryloxycarbonyl group, a carboxy group, a cyano group, a nitrile group, and at least one group selected from the group consisting of nitro groups, R １ ~R ４ does not have a phosphorus atom and does not represent a hydrogen atom at the same time. )

2. R in the general formula (A) １ and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or an alkenyl group having 2 to 10 carbon atoms which may have a substituent. The palladium complex according to claim 1.

3. R in the general formula (A) １ and R ２ are linked to represent an alicyclic structure which may have a substituent, a heterocyclic structure which may have a substituent, or a π-allyl structure which may have a substituent. The palladium complex according to claim 1.

4. R in the general formula (A) １ and R ２ are linked to represent a heterocyclic structure having 1 to 10 carbon atoms which may have a substituent, a cycloalkyl structure having 1 to 10 carbon atoms which may have a substituent, or a π-allyl structure having 3 to 10 carbon atoms which may have a substituent. The palladium complex according to claim 3.

5. R in the general formula (A) １ and R ２ represent an acetylacetonato group, a cinnamyl group, a crotyl group, or an allyl group. The palladium complex according to claim 4.

6. R in the general formula (A) ５ and R ６The palladium complex according to any one of claims 1 to 5, wherein is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

7. The palladium complex according to any one of claims 1 to 6, wherein X in the general formula (A) is a chlorine atom.

8. A coupling reaction catalyst comprising the palladium complex according to any one of claims 1 to 7.

9. A method for producing a palladium complex represented by the general formula (A) according to claim 1, comprising: a step of reacting a palladium compound represented by the following general formula (a) with a phosphine compound represented by the following general formula (b) to obtain the palladium complex, which is a method for producing a palladium complex. 【Chemical formula 2】 【Chemical formula 3】 (In the formula, X, R １ ~R ６ have the same definitions as in claim 1.)

10. In the presence of the palladium complex according to any one of claims 1 to 7, an aromatic boronic acid compound (B) or an aromatic boronic acid ester (B') and an aromatic compound (C) are subjected to a coupling reaction to produce a carbon-carbon coupling reaction product (D), which is a method for producing an aromatic compound.

11. The production method according to claim 10, wherein the reaction temperature of the coupling reaction is 40°C or lower.

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