Investigation Of Asymmetric Transformations Based On Cooperative Catalysis

Cooperative catalysis refers to the fact that different kinds of catalysts in the same reaction system participate cooperatively to achieve significant enhancement in catalytic activity and/or selectivity through synergism,relay and combination pathway.In the field of modern synthetic chemistry,the cooperative catalytic system involving two or more catalysts can promote the reaction which cannot be realized,and make the synthesis of complex target molecules from simple and easy accessible starting materials through one pot strategy.In this paper,we investigated the asymmetric allylation dearomatization of naphthols and catalyzed by transition metal and phosphoric acid cooperative catalysts and the isomerization of chiral dihydropyridone compounds in the presence of two bases.This thesis was divided into three chapters:In the first chapter,the cooperative-catalysis has become an effective strategy,which can improve the efficiency of various reactions,and has attracted more and more attention by researchers all over the world.This chapter mainly introduces the research progress of the cooperative catalysis in asymmetric synthesis in recent years.In the second chapter,the asymmetric allyllic dearomatization of naphthol derivatives and branched allyl alcohols catalyzed by chiral iridium complexes and phosphoric acid were described.The reaction conditions were carefully optimized and achieved various desired dearomitized products in good to high yields and excellent chemo-and enantioselectivities.And a plausible mechanism was proposed.In the third chapter,the DBU/K₂CO₃ catalyzed stereoselective isomerization of chiral dihydropyridone derivatives was studied.The isomerized products could be obtained in good to excellent yields,and the enantioselectivities were kept with 100%es'for almost all cases.The investigation of the reaction mechanism was undertaking in our laboratory.