Facile synthesis of multisubstituted benzo[b]furans via 2,3-disubstituted 6,7-furanobenzynes generated from ortho-iodoaryl triflate-type precursors

Abstract

2,3-Disubstituted 6,7-furanobenzynes were efficiently generated from ortho-iodoaryl triflate-type precursors using a silylmethyl Grignard reagent as the activator. The reactions between 6,7-furanobenzynes and unsymmetrical arynophiles proceeded in a highly regioselective manner. Since a variety of precursors were easily synthesizable from readily available 2,3-disubstituted 6-hydroxybenzofurans, this method enabled facile synthesis of a wide range of multisubstituted benzofurans, including π-extended molecules.