Manganese Catalyzed Enantioselective Epoxidation of <i>α</i>,<i>β</i>‐Unsaturated Amides with H<sub>2</sub>O<sub>2</sub>
Roman V. Ottenbacher, Vladimir I. Kurganskiy, Evgenii P. Talsi, Konstantin P. Bryliakov
Abstract
Abstract Herewith, we report the enantioselective epoxidation of electron‐deficient cis ‐ and trans‐α , β ‐unsaturated amides with the environmentally benign oxidant H 2 O 2 . The catalysts ‐ manganese complexes with bis ‐amino‐ bis ‐pyridine and structurally related ligands ‐ exhibit reasonably high efficiency (up to 100 TON) and excellent chemo‐ and enantioselectivity (up to 100% and 99% ee , respectively). Crucially, the cis ‐enamides epoxidation enantioselectivity and yield are dramatically enhanced by the presence of NH‐moiety, which effect can be explained by the hydrogen bonding interaction between the cis ‐enamide substrate and the manganese based oxygen transferring species. magnified image