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LATTICE-CONTROLLED SOLID STATE-SPECIFIC AND ENANTIOSELECTIVE REACTIONS

晶格控制的固态特异性和对映选择性反应

基本信息

批准号：
04640516
负责人：
OHGO Yoshiaki
金额：
$ 1.28万
依托单位：
NIIGATA COLLEGE OF PHARMACY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Previously, we found solia state-specific phenomenon in the photoracemization of optically active alkyl cobaloxime complexes. We also found solid state-specific and unidirectional (betha to alpha) photoisomerization of 2-substituted ethyl cobaloxime complexes.This study was carried out to clarify the mechanism for the above mentioned solid state-specific phenomenon and to find chiral lattice-controlled asymmetric (betha to alpha) photoisomerization, and the following results [ (1)- (3)] were obtained.(1) The solid state-specific phenomenon in the photoracemization of optically active alkyl cobalocime complexes was attributed (ascribed) to an unsymmetrical restriction of the reactive group by an intermolecular interaction such as hydrogen bonding.(2) Solid-state asymmetric photoisomerization occurred to afford optically active 1-substituted ethyl cobaloxime complexes with moderate to high enantioselectivities (up to 88%ee) upon visible light-irradiation on 2-cyanoethyl, 2-methoxycarbonylethyl, and N-substituted 2-carbamoylethyl cobaloximes coordinated with chiral axial ligand which has no asymmetric effect on the reactive group at the trans position in the same molecule but serves as the chiral handle for forming the chiral lattice.(3) The X-ray crystallographic analyzes of a series of 2-cyanoethyl and 2-methoxycarbonylethyl cobaloximes revealed that the 2-substituted ethyl group in a complex bringing about high enantioselectivity is apt to take a conformation parallel to the inplane ligand and is also forced to take a chiral conformation by chiral lattice, while the reactive group in a complex bringing about low enantioselectivity take a conformation perpendicular to the inplane ligand.

在此之前，我们发现了光学活性烷基钴肟配合物光消旋化过程中的SOLI态特有现象。我们还发现了2-取代乙基钴酮络合物的固相特异性和单向(比α)光异构化。本研究旨在阐明上述固相特有现象的机理，并发现手性晶格控制的不对称(比α)光异构化，得到了以下结果[(1)-(3)].(1)光学活性烷基钴配合物光消旋化中的固态特有现象归因于分子间相互作用(如氢键)对反应基团的不对称限制.(2)在可见光照射下，2-氰乙基，2-甲氧基碳乙基发生固态不对称光异构化反应，得到光学活性的1-取代乙基钴肟配合物，对映体选择性达88%，N-取代的2-氨甲酰乙基钴肟与手性轴向配体配位，对同一分子中反式位置上的反应基团没有不对称作用，但作为手性手性晶格的手性把手。(3)对一系列2-氰乙基和2-甲氧基碳乙基钴肟的X-射线晶体分析表明，具有较高对映体选择性的配合物中的2-取代乙基倾向于与平面内配体平行的构象，并被手性晶格强迫形成手性构象，而低对映选择性的络合物中的反应基团则以垂直于配位平面的方式发生构象。