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Design of Synergistic Function and Dynamic Stereocontrol of Hetero multi-metal complexes

杂多金属配合物的协同功能与动态立体控制设计

基本信息

批准号：
10555319
负责人：
MIKAMI Koichi
金额：
$ 5.95万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10555319/
关键词：
Asymmetric activation Dynamic stereocontrol Hetero multi-metal complexes Asymmetric catalysis Vitamin D Ene reaction Vitamin D derivatives Asymmetric synthesis Biological activity Differentiation

项目摘要

While non-racemic catalysts can generate non-racemic products with or without the "non-linear relationship" in enantiomeric excesses between catalysts and products, racemic catalysts inherently give only a racemic mixture of chiral products. Asymmetric catalysts can be further evolved into highly activated catalysts by association with chiral activators. This asymmetric activation process is particularly useful in racemic catalysis through selective activation of the one enantiomer of the racemic catalysts. Recently, a strategy whereby a racemic catalyst is selectively deactivated by a chiral additive has been reported as "chiral poisoning" to yield non-racemic products. 'Asymmetric activation' is an alternative but conceptually opposite strategy to asymmetric catalysts in which a chiral activator selectively activates rather than deactivates one enantiomer of a racemic chiral catalyst. The advantage of this activation strategy over the deactivation counterpart is that the activated catalyst can produce a greater enantiomeric excess (x_<act>% ee) in the products, even when using a catalytic amount of activator per chiral catalyst, than the ee attained by the enantiomerically pure catalyst on its own.Therefore, 'asymmetric activation' could provide a general and powerful strategy for the use of not only chirally rigid, racemic ligands but also chirally flexible ligands without enantiomeric resolution!

虽然非外消旋催化剂可以产生非外消旋产物，在催化剂和产物之间存在或不存在对映体过量的“非线性关系”，但外消旋催化剂固有地仅产生手性产物的外消旋混合物。不对称催化剂通过与手性活化剂结合可以进一步发展成为高活性催化剂。这种不对称活化方法在通过选择性活化外消旋催化剂的一种对映异构体的外消旋催化中特别有用。最近，一种策略，其中外消旋催化剂选择性失活的手性添加剂已被报道为“手性中毒”，以产生非外消旋产品。“不对称活化”是不对称催化剂的替代但概念上相反的策略，其中手性活化剂选择性地活化而不是使外消旋手性催化剂的一种对映异构体失活。这种活化策略相对于失活对应物的优点在于，<act>即使当每个手性催化剂使用催化量的活化剂时，活化的催化剂也可以在产物中产生比由对映体纯催化剂自身获得的ee更大的对映体过量（x_ % ee）。外消旋配体，而且手性柔性配体没有对映体拆分！