Bicyclic guanidine-catalyzed asymmetric Michael additions of 3-benzyl-substituted oxindoles to N-maleimides.

A bicyclic guanidine-catalyzed Michael addition of 3-benzyl substituted oxindoles to N-maleimides has been developed to produce oxindole derivatives with a quaternary carbon chiral center at the 3-position in excellent yields and enantio- and diastereoselectivities. This is the first incorporation of N-benzylic α-branched succinimides into 3,3-disubstituted oxindoles.