Electrophilic Cyclization of o-Anisole- and o-Thioanisole-Substituted Ynamides­: Synthesis of 2-Amidobenzofurans and 2-Amidobenzothiophenes

A facile synthesis of 3-substituted 2-amidobenzofurans and 2-amidobenzothiophenes via electrophilic cyclization reaction of o -anisole- and o -thioanisole-substituted ynamides with I 2 , NBS and NCS was developed. The products 3-iodo-2-amidobenzofurans were further transferred into 3-aryl-, 3-alkynyl, and 3-vinyl-2-amidobenzofurans via Pd-catalyzed reactions such as Suzuki–Miyaura and Sonogashira cross-coupling reactions and the Heck reaction.