Catalytic asymmetric amidohydroxylation of olefins with n-halo carboxamides

摘要

β-Hydroxyamides are synthesized from olefin substrates by means of a catalyzed asymmetric addition reaction. N-halo carboxamides are employed as the oxidant nitrogen source for the production of the β-hydroxysulfonamides. The addition reaction is catalyzed by osmium and is co-catalyzed by chiral ligands. The chiral ligands, in addition to being co-catalysts with the osmium, also serve to direct the addition reaction regioselectively and enantio-selectively. Divalent ligands are preferred over monovalent ligands because of their enhanced regio- and enantio-selectivity. Excellent yields and enantiomeric efficiencies are achieved with both organic solvents (homogeneous conditions) and co-solvent conditions (heterogenous conditions), generally containing a 50/50 (v/v) mixtures of water and organic solvent.