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