Visible-light-induced cascade radical sulfonation/annulation/isomerization reactions of propargyl chalcones with sodium sulfinates: Regioselective synthesis of sulfonyl 2H-chromene and 2H-quinoline derivatives

A cascade approach has been developed for the one-pot three-step synthesis of sulfonyl-containing 2 H -chromenes and 2 H -quinoline derivatives from propargyl chalcones and sodium sulfinates. This protocol features only sodium sulfinates, as sulfonyl radical precursors can promote regioselective sulfonation/annulation reactions under visible-light photoredox conditions. Notably, the olefin isomerization smoothly proceeds, delivering only 2H -chromenes and 2H -quinoline products in the present protocol. The reaction shows a metal-free, mild condition reaction, broad functional group tolerance, and very good yields. A cascade approach has been developed for the one-pot three-step synthesis of sulfonyl-containing 2H -chromenes and 2H -quinoline derivatives from propargyl chalcones and sodium sulfinates. This protocol features only sodium sulfinates as sulfonyl radical precursors can promote regioselective sulfonation/annulation reactions/isomerization, delivering only 2H -chromenes and 2H -quinoline products. The reaction shows a metal free, mild condition reaction, and broad functional group tolerance.