Enantioselective Catalytic Oxidation of Olefins and Organosulfur Compounds by Chiral Mn(II) Diamino-Dicarboxylato or Disulfonato Complexes via a Pentacoordinate Mn(V)-Oxo Cation

The scope of a recently reported chiral Mn(II)-complex (1) catalyzed enantioselective epoxidation of olefins has been extended to include mono- and Z-1,2-disubstituted olefinic substrates. In addition, the enantioselective conversion of sulfides to sulfoxides and RSX to R(SO)X is described. Excellent yields and enantioselectivities have been realized with just 3 mol % of Mn catalyst, which can be recovered for reuse. The absolute configuration of the product is in each case predicted on the basis of an axially symmetric, trigonal bipyramidal Mn(V)-oxo intermediate (e.g., 11a) as the effective oxidant. The sulfonate analogue (15) of the carboxylato complex 1 is an equally effective catalyst for enantioselective oxidation.