Visible-Light-Driven Sulfonylation/Cyclization of 1,5-Enynes with Sulfonyl Chlorides via Catalytic TBAI EDA Complexes: Access to 4-Cyano-1-sulfonyl Naphthalenes

A metal-free photocatalytic method achieves the selective radical cyclization of 1,5-enynes to construct naphthalene skeletons. This method utilizes an in situ-formed electron donor–acceptor (EDA) complex between sulfonyl chlorides and catalytic TBAI, delivering 4-cyano-1-sulfonyl naphthalenes through a 6- endo cyclization or a 5- exo-trig addition/3- exo-trig cyclization/ring expansion sequence. This one-pot transformation exhibits broad substrate scope and excellent functional group tolerance, efficiently forging both C–S and C–C bonds.