Desymmetrization and diastereotopic group selection in 1,4-cyclohexadienes

Diastereotopic group selection in 1,4-cyclohexadienes is a useful approach to synthesize rather complex compounds in a single operation. The stereoinduction occurs via a covalently bound stereogenic center. Cycloadditions, Michael additions, and radical reactions have been conducted as group-selective processes. Even more elegant is the desymmetrization of an achiral 1,4-cyclohexadiene. Various chiral reagents have been used successfully to desymmetrize 1,4-cyclohexadienes. In one step, at least two new stereogenic centers are formed. Chiral quaternary carbon centers can be obtained with high selectivity. This Account will provide an overview on diastereotopic group selection and desymmetrization in various 1,4-cyclohexadiene derivatives. 1 Introduction 2 Diastereotopic Group-Selective Processes 2.1 Cycloaddition 2.2 Michael Additions 2.3 Radical Processes 3 Desymmetrizations 3.1 Oxidations 3.2 Transition-Metal-Mediated Processes 3.3 Metalated Cyclohexadienes 4 Conclusions.