Gold and BINOL-phosphoric Acid Catalyzed Enantioselective Hydroamination/n-Sulfonyliminium Cyclization Cascade.

A highly enantioselective hydroamination/N-sulfonyliminium cyclization cascade is reported using a combination of gold(I) and chiral phosphoric acid catalysts. An initial 5-exo-dig hydroamination and a subsequent phosphoric acid catalyzed cyclization process provide access to complex sulfonamide scaffolds in excellent yield and high enantiocontrol. The method can be extended to lactam derivatives, with excellent yields and enantiomeric excesses of up to 93% ee.