Process for preparing asymmetric compound by using metal complex

Details Process for preparing asymmetric compound by using metal complex Process for preparing asymmetric compound by using metal complex

1997-12-05

1998-12-08

Richter, Johann

Organic compounds -- part of the class 532-570 series

Organic compounds

Phosphorus esters

560126, C07F 902, C07C 6974

Patent

active

058471863

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention relates to a metal complex which can be used in the preparation of an asymmetric compound useful in the fields of medicines, agricultural chemicals, perfumes, liquid crystals, and the like. More particularly, it relates to a metal complex by which an optically active reaction product having high optical purity can be obtained in high yield when it is used as a catalyst for asymmetric Michael addition reaction, asymmetric hydrophosphonylation reaction, or the like, as well as a process for producing an asymmetric compound using a solution of the metal complex.


BACKGROUND OF THE INVENTION

The present inventors previously studied an asymmetric synthesis reaction using a metal complex catalyst of a rare earth metal element and, as a result, found that a metal complex prepared by a method of mixing lanthanum chloride (LaCl.sub.3) and optically active dilithium binaphthoxide in tetrahydrofuran and adding water and sodium hydroxide thereto, or by a method of successively adding optically active binaphthol, water, and lithium chloride to a solution of La.sub.3 (O-tC.sub.4 H.sub.9).sub.9 (lanthanum t-butoxide) in tetrahydrofuran containing sodium tert-butoxide, can catalyze an asymmetric nitroaldol reaction to afford a nitroaldol product having high optical purity (J. Am. Chem. Soc., Vol. 114, p. 4418 (1992)).
In addition, the present inventors revealed that a complex prepared by adding 1 mole equivalent of optically active binaphthol to La(O-iC.sub.3 H.sub.7).sub.3 (lanthanum isopropoxide) can catalyze an asymmetric Michael reaction to afford a Michael adduct having high optical purity (J. Synth. Org. Chem., Jpn., Vol. 51, p. 972 (1993); J. Am. Chem. Soc., Vol. 116, p. 1571 (1994)).
Further, the present inventors found that a metal complex, i.e., La--K-Binol (LPB), can act as an effective catalyst in imine-hydrophosphonylating reaction to afford a hydrophosphonyl compound having high optical purity (J. Org. Chem., Vol. 60, p. 6656 (1995)).
In addition, it was found that a metal complex, La--Li-Binol (LnLB), can act as an effective catalyst in an aldehyde-hydrophosphonylating reaction to afford an asymmetric hydrophosphonylated compound (Tetrahedron: Asymmetry, Vol. 4, p. 1783 (1993); Tetrahedron Lett., Vol. 35, p. 227 (1994)).
However, lanthanum, which is a rare earth metal element contained in the aforementioned metal complexes, is difficult to obtain and, thus, the development of metal complex catalysts without using a rare earth metal is desired. However, such metal complex catalysts are not yet known.
On the other hand, an asymmetric Michael reaction product and an asymmetric .alpha.-hydrophosphonylated compound are both known as useful asymmetric compound reaction products. Particularly, a hydroxy phosphorylated compound has potent bioactivity and is expected to act effectively as an enzyme inhibitor for a synthesis enzyme such as renin, EPSP synthase, HIV protease, and the like and, thus, the development of an optically selective process for synthesizing these asymmetric phosphorylated compounds is desired. However, even when the above metal complex, Ln--Li-Binol (LnLB), is used in this application, either optical purity or yield of the resulting phosphorylated compound is not satisfactory. In addition, a reaction at an extremely low temperature is inevitably required. Thus, the above application has suffered many unsolved problems as an industrial process for preparing the above compounds.


SUMMARY OF THE INVENTION

The present invention provides a metal complex, or a solution of the metal complex, that can be used as a catalyst in an asymmetric Michael reaction and in an asymmetric hydrophosphonylation reaction, contains no rare earth metal element, and can afford an optically active compound having high optical purity at high yield. The present invention also provides a process for producing an asymmetric compound by an asymmetric Michael reaction and an asymmetric hydrophosphonylation reaction using such the metal complex.
The present inventors further st

REFERENCES:
patent: 4965398 (1990-10-01), Mikami et al.
H. Sasi et al., J. Am. Chem. Soc., 114, p. 4418 (1992).
M. Shibasaki et al., J. Synth. Org. Chem., Japan, 51, p. 972 (1993).
H. Sasai et al., J. Am. Chem. Soc., 116, p. 1571 (1994).
H. Sasai et al., J. Org. Chem., 60, p. 6656 (1995).
T. Yokomatsu et al., Tetrahedron: Asymmetry, 4, p. 1783 (1993).
N. P. Rath, Terahedron lett., 35(2), p. 227 (1994).

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