Bismuth- and hafnium-catalyzed hydroamination of vinyl arenes with sulfonamides, carbamates, and carboxamides

Catalytic intermolecular hydroamination of vinyl arenes is described. Our initial investigation revealed that a Bi(OTf)(3)/[CU(CH3CN)(4)]PF6 system previously developed for catalytic intermolecular hydroamination of 1,3-dienes was suitable for hydroamination of a styrene with sulfonamides, but the substrate generality of this system was unsatisfactory. Several-metals were screened to expand the substrate scope, and a new Hf(OTf)(4)/[CU(CH3CN)(4)]PF6 System was determined to be highly suitable. The combination of Hf(OTf)(4) and [Cu-(CH3CN)(4)]PF6 efficiently promoted the hydroamination of various vinyl arenes, including less-reactive vinyl arenes with electron-withdrawing groups. This strategy was applied to sulfonamides, carbamates, and carboxamides, and products were obtained in up to 99% yield with 0.3-10 mol% catalyst loading.