Synthesis of benzothiophene derivatives from dilithio reagents, sulfur, and electrophiles via electrophilic cyclization

Benzothiophene derivatives were synthesized in high yields from readily available o-(alkynyllithio)aryllithio compounds, sulfur, and 2 equiv of acid chlorides or other electrophiles. An acid chloride-induced electrophilic cyclization resulted in the formation of the thiophene ring.