Rhodium-Catalyzed Stereoselective Amination of Thioethers with N-Mesyloxycarbamates: DMAP and Bis(DMAP)CH2Cl2 as Key Additives

A stereoselective Rh‐catalyzed intermolecular amination of thioethers using a readily available chiral N‐mesyloxycarbamate to produce sulfilimines in excellent yields and diastereomeric ratio is described. A catalytic mixture of 4‐dimethylaminopyridine (DMAP) and bis(DMAP)CH2Cl2 proved pivotal in achieving high selectivity. The X‐ray crystal structure of the (DMAP)2⋅[Rh2{(S)‐nttl}4] complex was obtained and mechanistic studies suggested a RhII‐RhIII complex as the catalytically active species. The select committee: A mixture of 4‐dimethylaminopyridine (DMAP) and bis(DMAP)CH2Cl2 proved pivotal in achieving high selectivity in the Rh‐catalyzed intermolecular amination of thioethers with a readily available chiral N‐mesyloxycarbamate to produce sulfilimines in excellent yields. Mechanistic studies suggest a RhII‐RhIII complex to be the catalytically active species.