Advancements in Catalytic Asymmetric Intermolecular Ene-Type Reactions

The asymmetric ene reaction is an important transformation that provides synthetically valuable allylic derivatives efficiently and enantioselectively. Hence, significant attention has been paid to developing highly efficient chiral catalytic systems to address the issues of reactivity, stereoselectivity, substrate generality, cost and operational simplicity of the process. This review summarizes the advancements of enantioselective intermolecular ene-type reactions involving three kinds of ene components. With particular emphasis on the development and characteristics of various chiral catalysts used, comparisons are made between the related reactions. 1 Introduction 2 Unactivated Alkenes as Ene Components 2.1 Asymmetric Carbonyl Ene Reactions with Active Aldehydes as the Enophiles 2.2 Asymmetric Carbonyl Ene Reactions with Active Ketones as the Enophiles 2.3 Asymmetric Imino Ene Reactions with Imines as the Enophiles 3 Enol Ethers as Ene Components 4 Enamides and Enecarbamates as Ene Components