Pd-Catalyzed C—S Cyclization via C—H Functionalization Strategy: Access to Sulfur-containing Benzoheterocyclics

A C—H sulfurated cyclization protocol starting from thioacetates is developed for straightforward construction of sulfur-containing benzoheterocyclics. The diversiform functional dihydrobenzothiophenes and thiochromans were comprehensively achieved through the Pd-catalyzed carbon- sulfur cyclization. Mechanistic studies indicated that C—H bond cleavage was involved in the rate-determining step. [1]Benzothieno-[3,2-b]- [1]benzothiophene (BTBT) and benzo[b]thieno[2,3-d]thiophene (BTT) were efficiently established as the well-known organic field-effect transistor (OFET) material molecules through this methodology.