Asymmetric epoxidation of α,β-unsaturated ketones catalyzed by silica-grafted poly-(l)-leucine catalysts

A practical procedure has been developed for grafting poly(amino acid) on silica gel as an efficient and recoverable catalyst in the Juliá–Colonna asymmetric epoxidation with high enantioselectivities. Separation and recovery of the catalyst of poly(amino acid) have been remarkably improved by grafting on silica gel without a significant loss of enantioselectivity and activity.