Enantioselective Dearomatization of Substituted Phenols via Organocatalyzed Electrophilic Amination.

Highly efficient and stereoselective dearomatization of substituted phenols was achieved via chiral phosphoric acid-catalyzed electrophilic para -amination with commercially available azodicarboxylates. This protocol readily afforded a series of chiral 2,5-cyclohexadienones bearing 4-aza-quaternary stereocenters with excellent yields and enantioselectivities (≤99% yield and >99% ee). Easy scale-up of this reaction to a gram scale and diverse derivatizations of the chiral products into α-tertiary amines and α-tertiary heterocycles derivatives well demonstrated the potential of this method.