asymmetric cycloaddition reaction of fluoromethyl-substituted nitroalkenes with azomethine ylides was developed using a catalyst derived from copper(I) perchlorate and a commercially available, chiral Walphos ligand. This method provides a simple approach to optically active exo-3-(fluoromethyl)proline derivatives in high yields, as well as in high diastereo- and enantioselectivities. 1,3-dipolar cycloaddition