Asymmetric Epoxidation of Olefins with Sodium Percarbonate Catalyzed by Bis -amino- bis -pyridine Manganese Complexes.

Asymmetric epoxidation of a series of olefinic substrates with sodium percarbonate oxidant in the presence of homogeneous catalysts based on Mn complexes with bis-amino-bis-pyridine ligands is reported. Sodium percarbonate is a readily available and environmentally benign oxidant that is studied in these reactions for the first time. The epoxidation proceeded with good to high yields (up to 100%) and high enantioselectivities (up to 99% ee ) using as low as 0.2 mol. % catalyst loadings. The epoxidation protocol is suitable for various types of substrates, including unfunctionalized alkenes, α , β -unsaturated ketones, esters ( cis - and trans -), and amides ( cis - and trans -). The reaction mechanism is discussed.