Highly enantioselective asymmetric 1,3-dipolar cycloaddition of azomethine ylide catalyzed by a copper(I)/ClickFerrophos complex

A copper(I)/ClickFerrophos complex catalyzed the asymmetric 1,3-dipolar cycloaddition reaction of methyl N-benzylideneglycinate (the source of azomethine ylides) with vinyl sulfone to give the exo-2,4,5-trisubstituted pyrrolidine in good yield with high enantioselectivity (99% ee). The complex also effectively catalyzed reactions of other dipolarophiles such as acrylates, maleate, and maleimides to give the exo-2,4,5-, and 2,3,4,5-substituted pyrrolidine derivatives with high diastereo- and enantioselectivities.