Transition-Metal-Free Diarylannulated Sulfide and Selenide Construction via Radical/Anion-Mediated Sulfur–Iodine and Selenium–Iodine Exchange

A facile, straightforward protocol was established for diarylannulated sulfide and selenide construction through S–I and Se–I exchange without transition metal assistance. Elemental sulfur and selenium served as the chalcogen source. Diarylannulated sulfides were systematically achieved from a five- to eight-membered ring. A trisulfur radical anion was demonstrated as the initiator for this radical process via electron paramagnetic resonance (EPR) study. OFET molecules [1]­benzo­thieno­[3,2-b]­[1]­benzo­thio­phene (BTBT) and [1]­benzo­thieno­[3,2-b]­[1]­benzo­seleno­phene (BTBS) were efficiently established.