Enantioselective aza-Diels-Alder reaction of Brassard's diene with aldimines catalyzed by chiral N,N′-dioxide-Yb(OTf)3 complex

The chiral N,N'-dioxide-Yb(OTf)(3) complex-catalyzed enantioselective aza-Diels-Alder reaction of Brassard's diene with aldimines has been developed, giving the corresponding alpha,beta-unsaturated delta-lactam derivatives in moderate yields with good enantioselectivities (up to 81% ee and up to 99% ee by single recrystallization) under mild conditions. Isolation of the reaction intermediate indicates that this asymmetric aza-Diels-Alder reaction proceeds through a stepwise Mannich-type pathway. (C) 2010 Elsevier Ltd. All rights reserved.