Pyridine-N-oxide catalyzed asymmetric N-acylative desymmetrization of sulfonimidamides.

A highly efficient enantioselective N-acylative desymmetrization of sulfonimidamides with chloroformates was reported using chiral 4-arylpyridine-N-oxide as the catalyst, affording N-acylative sulfonimidamides with sulfur(vi)-stereocenters in high yields and excellent enantioselectivities. Experiments and DFT calculations support an acyl transfer mechanism, and the nucleophilic substitution of sulfonimidamide by the O-acyloxypyridinium cation intermediate is the enantio-determining step of the reaction. The reaction features variability for acyloxy groups and compatibility with moisture.