Chiral hydroperoxides have a significant influence on the enantioselectivity of the metal-catalyzed asymmetric Baeyer-Villiger oxidation of cyclic ketones and the epoxidation of allylic alcohols, when chiral ligands are employed. If both the ligand and the hydroperoxide are enantiopure. the ligand determines the formation of the preferred product enantiomer in both reactions. (C) 2001 Elsevier Science Ltd. All rights reserved.