Visible-light promoted sulfonamidation of enol acetates to α-amino ketones based on redox-neutral photocatalysis

A visible-light mediated photoredox-catalyzed sulfonamidation of enol acetates to alpha -amino ketones has been developed. Upon irradiation with a blue LED (lambda 425 +/- 15 nm) in the presence of catalytic amounts of Ir(ppy)(3) (2 mol%), N-arylsulfonyl-1-aminopyridine salts were transformed into N-centered radical intermediates, which then underwent coupling with enol acetates to give alpha -sulfonylamino ketones in up to 83% yield. The process features mild and operationally simple reaction conditions and does not require an external oxidant.