Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
1999-12-10
2004-03-16
Raymond, Richard L. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C502S155000
Reexamination Certificate
active
06706905
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a palladium-phosphine complex compound, which is useful as a catalyst of organic synthesis.
Hitherto, various transition metal complexes have been used as catalysts of organic synthesis. In particular, noble metal complexes are stable and easy to handle. Thus, they are widely used as catalysts for organic synthesis, although they are high in price. Of optically active ligands of transition metal complexes used in asymmetric catalytic reactions, a ligand of 2,2′-bis(diphenylphosphino)-1,1′-binaphtyl (hereinafter referred to as “BINAP”) is one of the most superior ligands in asymmetry differentiation capability. It has been reported in J. Am. Chem. Soc., 1991, Vol. 113, pp. 1417 and J. Org. Chem., 1989, Vol. 54, pp. 4738 that a palladium complex having a ligand of BINAP is very much superior in catalytic activity, particularly in enantio-selectivity, for Heck reaction to an olefin, which is an asymmetric carbon-carbon bond formation reaction. In such reaction, there is assumed an involvement of an intermediate of [PhPd(I)(BINAP)], which is formed by an oxidative addition of benzene iodide to Pd(0)-BINAP formed in the reaction system.
There are known palladium complex compounds having ligands of trifluoromethylphenyl and tris(trifluoromethyl)phenyl, which are represented by the general formulas:
where Y is fluorine, chlorine, bromine, or iodine.
J. Organomet. Chem., 1971, 28, 287 discloses a method for producing a palladium complex compound represented by the general formula Ar
1
Pd(PPh
3
)
2
X
1
where Ar
1
represents an aryl and X
1
is a halogen. In this method, a stable palladium complex Pd
0
(PPh
3
)
4
is reacted with an aryl halide. Organometallics, 1996, 15(17), 3708 discloses a similar method in which a palladium complex Pd
2
(dba)
3
is used.
J. Chem. Commun., 1994, 121 discloses a reaction of dibromobis(triphenylphosphine)palladium(II) with toluene in the presence of potassium carbonate at 130 for 1 hr to obtain a small amount of bromo[methylphenyl]bis(triphenylphosphine)palladium(II).
J. Am. Chem. Soc., Vol. 117, No. 15, 4305 (1995) discloses a method for producing a palladium complex compound having a benzoato ligand, represented by the formula (Ph
3
P)
2
PdPh(PhCOO). In this method, (Ph
3
P)
2
Pd
2
Ph
2
(&mgr;-OH)
2
is dispersed in benzene. Then, benzoic acid is added to the mixture to have a solution having a pale yellow color. Then, the solvent is distilled away. After that, n-hexane is added, thereby obtaining (Ph
3
P)
2
Pd
2
Ph
2
(&mgr;-PhCOO)
2
in the form of crystal. The obtained crystals are dispersed in benzene. Then, triphenylphosphine is added, thereby preparing a transparent solution. Then, the solvent is distilled away. After that, n-hexane is added, thereby obtaining the aimed palladium complex compound in the form of crystal.
J. Organomet. Chem. 553 (1998) 83-90 discloses a method for producing trans-[Pd(OOC—(C
6
H
4
)-2-SMe—&kgr;
1
—O)Ph(PPh
3
)
2
]. In this method, a thallium salt 2-RS—C
6
H
4
—COOTl is prepared by reacting 2-RS—C
6
H
4
—COOH with thallium carbonate in ethanol. Then, the thallium salt is reacted with trans-[PdCl(Ph) (PPh
3
)
2
] in tetrahydrofuran, thereby obtaining the product with a precipitate of thallium chloride.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for easily producing a palladium complex compound that is useful as catalyst.
It is another object of the present invention to provide a palladium complex compound that is superior in physical and/or chemical properties.
According to a first aspect of the present invention, there is provided a first method for producing a first palladium-complex compound represented by the general formula (4). With this, it is possible to easily obtain the product by the following reaction steps (a) and (b). The first method comprises:
(a) reacting an aromatic compound represented by the general formula (1), with a palladium compound and a phosphine derivative, in the presence of a first basic substance, thereby obtaining a second palladium-complex compound represented by the general formula (2); and
(b) reacting said second palladium-complex compound with a benzoic acid represented by the general formula (3), in the presence of a second basic substance, thereby producing said first palladium-complex compound,
Ar
1
X (1)
where Ar
1
is an aryl group; and X is a halogen that is fluorine, chlorine, bromine or iodine, trifluoromethanesulfonate group, an alkylsulfonate group having a carbon atom number of 1-4, or a substituted or unsubstituted arylsulfonate group,
Ar
1
—PdL
2
X (2)
where each L is independently a phosphine ligand, and Ar
1
and X are defined as above,
Ar
2
—COOH (3)
where Ar
2
is an aryl group,
where Ar
1
, Ar
2
, and L are defined as above.
According to a second aspect of the invention, there is provided a second method for producing the second palladium-complex compound represented by the general formula (2). With this, it becomes possible to easily obtain the product, using stable chemical substances that are easily obtainable. The second method comprises the reaction step (a) of the first method, thereby obtaining the second palladium-complex compound.
According to a third aspect of the invention, there is provided a third method for producing the first palladium-complex compound represented by the general formula (4). The third method comprises reacting a second palladium-complex compound represented by the general formula (2), with a benzoic acid represented by the general formula (3), in the presence of a basic substance, thereby producing the first palladium-complex compound.
According to a fourth aspect of the invention, there is provided a fourth method for producing the first palladium-complex compound represented by the general formula (4). As compared with the first method, the fourth method comprises a single reaction step of reacting an aromatic compound represented by the general formula (1), with a palladium compound, a phosphine derivative and a benzoic acid derivative represented by the general formula (3), in the presence of a basic substance, thereby obtaining the first palladium-complex compound.
According to a fifth aspect of the invention, there is provided a novel palladium complex compound. This compound, which can be produced by the above-mentioned first, third or fourth method, is represented by the general formula (5),
where Ar
3
and Ar
4
are respectively aryl groups represented by the general formulas (6) and (7), and each L is independently a phosphine ligand,
where R
2
is trifluoromethyl group, trifluoromethyoxy group, a halogen that is fluorine, chlorine, bromine or iodine, nitro group, acetyl group, cyano group, an alkyl group having a carbon atom number of 1-4, an alkoxyl group having a carbon atom number of 1-4, or an alkoxycarbonyl group having a carbon atom number of 2-5; and m is an integer of 0-4,
where R
1
is trifluoromethyl group, and n is an integer of 1-3.
According to a sixth aspect of the invention, there is provided a novel palladium complex compound. This compound, which can be produced by the above-mentioned second method, is represented by the general formula Ar
5
—PdL
2
X where Ar
5
is bis(trifluoromethyl)phenyl group, X is halogen that is fluorine, chlorine, bromine or iodine, and each L is independently a phosphine ligand.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The above-mentioned first to fourth methods according to the invention will be described in detail, as follows.
In the aromatic compound Ar
1
X used in the first, second and fourth methods and the second palladium-complex compound Ar
1
—PdL
2
X used in the third method, X is defined as above and preferably bromine or iodine in practical use.
In the aromatic compound Ar
1
X used in the first, second and fourth methods and the second palladium-complex compound Ar
1
—PdL
2
X used in the third method, Ar
1
is defined as being a
Hatano Manabu
Ishida Michio
Koide Makoto
Kume Takashi
Mikami Koichi
Balasubramanian Venkataraman
Raymond Richard L.
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