New Method for Asymmetric Synthesis by Using Chiral Bases

点击翻译按钮获取中文摘要

Enantioselctive synthesis and reactions of enolate ions are one of the important area in modern synthetic chemistry. The aim of this project is the design and synthesis of multidentate-type chiral lithium amides and the corresponding chiral amines, their applications to the enantioselective synthesis of chiral lithium enolates and to the enantioselective reactions of prochiral lithium enolates, and the development of these reactions to highly catalytic systems. We obtained the following results through this project.(1) The combination of a catalytic amount of a chiral amine and a stoichiometric amount of an achiral lithium amide has realized catalytic asymmetric deprotonation reactions of prochiral ketones.(2) The new C_2 symmetric chiral tetraamine has been found to be an excellent ligand for catalytic asymmetric alkylation of lithium enolates derived from alpha, alpha-disubstituted ketones.(3) Catalytic asymmetric protonation of prochiral ketones has been realized by using a catalytic amount of chiral tetraamine and a proton source which is hardly soluble in the solvent used.(4) Enantioselective Michael reactions of acyclic ketones have been realized by using a chiral tetraamine.