Highly Endo-Selective and Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Ylide with α-Enones Catalyzed by a Silver(I)/ThioClickFerrophos Complex

A silver(I)/ThioClickFerrophos complex catalyzed the highly endo-selective asymmetric 1,3-dipolar cycloaddition reaction of methyl N-benzylideneglycinate (the source of azomethine ylides) with (E)-acyclic alpha-enones having an endolexo ratio of 90/10 to 99/1. The highly functionalized endo-4-acyl pyrrolidines were obtained in good yields with high enantioselectivities (up to 98% ee). The complex also effectively catalyzed endo-selective reactions with 2-cyclopentenone to give the endo-bicyclic pyrrolidine in high enantioselectivity.