Sequential and One-Pot Reactions of Phenols with Bromoalkynes for the Synthesis of (Z)-2-Bromovinyl Phenyl Ethers and Benzo[b]furans

Benzo[b]furans were prepared in one pot based on the addition/palladium-catalyzed C-H bond functionalization of phenols with bromoalkynes. The addition reactions of phenols to bromoalkynes generated (Z)-2-bromovinyl phenyl ethers in high yields with excellent regio- and stereoselectivity. The obtained (Z)-2-bromovinyl phenyl ethers subsequently proceeded by intramolecular cyclization to afford 2-substituted benzo[b]furans in good yields through palladium-catalyzed direct C-H bond functionalizations. It is important to note that the transformation of phenols with bromoalkynes into benzo[b]furans could be carried out in one pot with a simple and efficient tandem procedure.