Primary-Secondary Diamine Catalyzed Enantioselective Synthesis of Substituted Cyclohex-2-enones by Cascade Michael–Aldol–­Dehydration of Ketones with Chalcones

Abstract

A simple primary-secondary diamine organocatalyst catalyzes the cascade Michael–aldol–dehydration of chalcones and unmodified ketones to produce substituted cyclohex-2-enones under mild conditions with good yields and high enantio- and/or diastereoselectivities. The success of the catalyst system is possibly due to simultaneous activation of the electrophilic chalcone by iminium formation and the nu­cleophilic ketone by enamine formation with an overall intramolecular iminium–di-enamine mechanism.