Visible-Light-Induced Direct Oxidative C-H Amidation of Heteroarenes with Sulfonamides.

A direct oxidative C-H amidation of heteroarenes with sulfonamides via nitrogen-centered radicals has been achieved. Nitrogen-centered radicals are directly generated from oxidative cleavage of N-H bonds under visible-light photoredox catalysis. Sulfonamides, which are easily accessed, are used as tunable nitrogen sources and bleach (aqueous NaClO solution) is used as the oxidant. A variety of heteroarenes, including indoles, pyrroles and benzofurans, can undergo this amidation with high yields (up to 92 %). These reactions are highly regioselective, and all the products are isolated as single regioisomer.