ASYMMETRIC SYNTHESIS OF OPTICALLY ACTIVE POLYMERS HAVING MAIN CHAIN CHIRALITY

具有主链构型手性的旋光性聚合物的合成是一项重要的技术，对下一代高分子材料的分子设计至关重要。包括C-C键形成反应在内的许多对映选择性转化方法已经得到了广泛的研究。如果不对称C-C成键反应在定量转化过程中进行，且无副反应，则可用于光学活性聚合物的合成。我们发现烯丙基硅烷在醛上的对映选择性加成反应（Sakurai-Hosomi烯丙基化反应）和烯醇硅烷在醛上的对映选择性加成反应（Mukaiyama醛醇反应）是合成光学活性聚合物的合适反应。双烯丙基硅烷和双醛之间的重复Sakurai-Hosomi烯丙基化产生具有手性均烯丙基醇单元结构的聚合物。采用手性改性路易斯酸催化剂，得到了具有主链构型手性的光学活性聚合物。类似地，双烯醇硅烷和醛之间的重复Mukaiyama醛反应产生具有手性β-羟基羰基单元结构的聚合物。

The synthesis of optically active polymers having main chain configurational chirality is an important technology, which is essential for the molecular design of the next generation polymeric materials. A great number of methods for enantioselective transformations including C-C bond forming reactions have been extensively studied. If an asymmetric C-C bond forming reaction proceeds in quantitative conversion without any side reactions, it can be used for optically active polymer synthesis. We have found that the enantioselective addition of allylsilane to an aldehyde (Sakurai-Hosomi allylation reaction) and the enantioselective addition of enol silane to an aldehyde (Mukaiyama aldol reaction) are suitable reaction for the synthesis of optically active polymers. Repetitive Sakurai-Hosomi allylation between bis(allylsilane) and dialdehyde produced a polymer having a chiral homoallylic alcohol unit structure. When a chirally modified Lewis acid catalyst was used, optically active polymers having main chain configurational chirality was obtained. Similarly, repetitive Mukaiyama aldol reaction between bis(enolsilane) andaldehyde produced a polymer having a chiral β-hydroxy carbonyl unit structure.