Generation of α-Iminyl Radicals from α-Bromo Cyclic N-Sulfonylimines and Application to Coupling with Various Radical Acceptors Using a Photoredox Catalyst.

Visible-light-induced generation of α-iminyl radicals was accomplished using α-bromo cyclic N-sulfonylimines and photoredox catalysts such as erythrosine B or Ru(bpy)3 (PF6 )2 . The generated α-iminyl radical was utilized for various radical reactions with allylation reagents, silyl enol ethers and allenyl stannane to give the corresponding coupling products. Furthermore, atom transfer radical addition (ATRA) to olefin proceeded to provide the ATRA product. This process provided a mild and efficient method for the synthesis of cyclic N-sulfonylimine-containing molecules that act as bioactive compounds and become the precursors in sultam synthesis.