Synthesis of benzo[ b ]furans from alkynyl sulfoxides and phenols by the interrupted Pummerer reaction.

The interrupted Pummerer reaction of alkynyl sulfoxides with phenols is disclosed. A wide range of benzo[ b ]furans were efficiently synthesized through unexplored electrophilic activation of the electron-deficient alkynyl sulfinyl group. Based on the good availability of alkynyl sulfoxides, we successfully prepared various functionalized benzo[ b ]furans from readily available alkynes, thiosulfonates, and phenols.