Modular Construction of 2-Substituted Benzo[b]furans from 1,2-Dichlorovinyl Ethers

(E)-1,2-Dichlorovinyl ethers and amides are easily accessible from trichloroethylene via nucleophilic addition across in situ synthesized dichloroacetylene. A one-pot, sequential Suzuki-Miyaura coupling/intramolecular direct arylation between dichlorovinyl ethers and organoboronic acids provides easy access to a variety of benzofurans in only two steps from inexpensive commercially available compounds. The method is extendable to the preparation of indoles from the analogous dichlorovinyl amides.