Synthesis of 2,3-Disubstituted Benzo[b]furans by the Palladium-Catalyzed Coupling ofo-Iodoanisoles and Terminal Alkynes, Followed by Electrophilic Cyclization

[reaction: see text] 2,3-Disubstituted benzo[b]furans are readily prepared under very mild reaction conditions by the palladium/copper-catalyzed cross-coupling of various o-iodoanisoles and terminal alkynes, followed by electrophilic cyclization with I2, PhSeCl, or p-O2NC6H4SCl. Aryl- and vinylic-substituted alkynes undergo electrophilic cyclization in excellent yields. Biologically important furopyridines can be prepared by this approach in high yields.