Palladium/,'-Disulfonyl Bisimidazoline-Catalyzed Enantioselective Addition of Arylboronic Acids to Cyclic -Sulfonyl Ketimines.

The combination of Pd(TFA) and an ,'-disulfonyl bisimidazoline ligand shows high catalytic activity and excellent asymmetric induction in the addition of arylboronic acids to cyclic -sulfonyl ketimines including benzo[]isothiazole-1,1-dioxides, benzo[][1,2,3]oxathiazine-2,2-dioxides, and 1,2,5-thiadiazole-1,1-dioxides, by which three types of chiral quaternary carbon-containing sultams with substantial substitution diversity were synthesized with high yields and excellent enantioselectivities (up to >99% ee). The current catalysis demonstrated a remarkable tolerance to oxygen and thus provided an operationally simple approach for constructing enantioenriched cyclic quaternary stereocenters.