Amine-catalyzed enantioselective 1,3-dipolar cycloadditions of aldehydes to C,N-cyclic azomethine imines

Abstract

Amine-catalyzed enantioselective 1,3-dipolar cycloadditions of aldehydes to C,N-cyclic azomethine imines were developed. The reactions between diversely substituted C,N-cyclic azomethine imines and aldehydes proceeded smoothly in the presence of chiral prolinol silyl ether catalyst and gave the C-1-substituted tetrahydroisoquinolines in a highly stereoselective manner. These tetrahydroisoquinolines could be efficiently transformed to several other useful polycyclic frameworks. Go cyclo! An efficient asymmetric 1,3-dipolar cycloaddition reaction catalyzed by a chiral prolinol silyl ether catalyst has been developed (see scheme). Removal of the benzamide group of the intermediates furnished the desired chiral C-1-substituted tetrahydroisoquinolines in high yields with excellent stereoselectivities. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.