Desymmetrization of cyclohexadienones via cinchonine derived thiourea-catalyzed enantioselective aza-Michael reaction and total synthesis of (-)-Mesembrine

Desymmetrization of cyclohexadienones via aza-Michael reaction catalyzed by cinchonine derived thiourea has been realized to afford a series of highly enantioenriched pyrrolidine and morpholine derivatives in excellent yields and ees. With this newly established methodology, asymmetric total synthesis of (-)-Mesembrine in high enantiomeric excess (98% ee) was accomplished.