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Solid-State Asymmetric Reaction by Use of Chiral Crystal Environment

利用手性晶体环境的固态不对称反应

基本信息

批准号：
09640651
负责人：
OHGO Yoshiaki
金额：
$ 2.11万
依托单位：
Niigata College of Pharmacy
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Solid state-specific and unidirectional photoisomerization and chiral lattice-controlled asymmetric (γ→β→α) photoisomerization of 3-cyanopropyl cobaloxime complexes were found to occur on visible light-irradiation of 3-cyanopropylcobaloxime complexes. Maximum enantioselectivities reached up to 91%ee. In general, the reaction rate of the second step (β→α) was much faster than that of the first step (γ→β) and the enantioselectivity of the second step was much higher than that of the first step.In extensive investigations of this type of reactions, we also found several unusual examples in which the reaction rate of the first step was faster than that of the second step or the enantioselectivity of the first step was higher than that of the second step.The configuration of the major enantiomer of alpha-complexes produced was found to be predictable from the shape of the reaction cavity drawn based on the crystal structure, in all cases examined, and the unusual results were also elucidated from the shape of the reaction cavity. Finally, we investigated X-ray crystal structure analyses of intermediate reaction stages of an interesting example in which the configuration of the major enantiomer had presumably been reversed on isomerization from the β-complex to the α-complex. Thus, we could directly observe the major enantiomer of the intermediate beta-substituted propyl complex, whose configuration and conformation agreed with those predicted from the shape of the reaction cavity of the 3-substituted propyl complex. By introducing large substituents such as phenyl or furyl group on the planar glyoxime ligand, the reaction rate was extremely enhanced in a series of 2-cyanoethyl complexes, and also enantioselectivity was extremely improved in a series of 2-methoxycarbonylethyl complexes.

在可见光照射下，3-氰丙基钴肟配合物发生了固相专一性的单向光异构化和手性晶格控制的不对称（γ→β→α）光异构化.对映体选择性最高可达91%ee.一般来说，第二步（β→α）的反应速率比第一步（γ→β）快得多，第二步的对映体选择性也比第一步高得多.在对这类反应的广泛研究中，我们还发现了几个不寻常的例子，其中第一步的反应速率比第二步快，或者第一步的对映选择性比第二步高。在所有检查的情况下，发现所产生的α-络合物的主要对映异构体的构型可从基于晶体结构绘制的反应腔的形状预测，并且还从反应腔的形状阐明了不寻常的结果。最后，我们研究了一个有趣例子的中间反应阶段的X射线晶体结构分析，其中主要对映异构体的构型可能在从β-络合物异构化为α-络合物时发生了逆转。因此，我们可以直接观察到中间体β-取代丙基络合物的主要对映体，其构型和构象与从3-取代丙基络合物的反应腔形状预测的那些一致。通过在平面乙二肟配体上引入苯基或呋喃基等大的取代基，在一系列2-氰乙基配合物中反应速率得到极大的提高，在一系列2-甲氧羰基乙基配合物中对映选择性也得到极大的改善。