Catalytic Asymmetric Synthesis of Aza-Quaternary Carbon Cyclohexadieneones Enabled by Aminative Dearomatization of Phenols.

Abstract

Reported herein is the catalytic asymmetric aminative dearomatization reaction of common phenols. As opposed to the well-studied indoles and naphthols, phenols are supposed to be challenging substrates for catalytic asymmetric dearomatization reactions in terms of their strong aromaticity and regioselectivity issues. Under the catalysis of a chiral phosphoric acid, the C4-regiospecific aminative dearomatization of phenols with azodicarboxylates readily occurred at ambient temperature, delivering an array of biologically and synthetically important aza-quaternary carbon cyclohexadieneones in good yields and with excellent enantioselectivities (29 examples, up to 98% yield, and >99% ee).