First example of opening and hydrogenation of 2,3-dihydrobenzo[b]thiophene to 2-ethylthiophenol assisted by a soluble metal complex

Abstract

Displacement of THF by dihydrobenzo[b]thiophene (DHBT) in [(triphos)Ir(H)2(THF)]BPh4 yields the η1-S-DHBT adduct [(triphos)Ir(H)2(η1-DHBT)]BPh4 which reacts in THF at room temperature with KOBut to give the neutral 2-vinylthiophenolate derivative (triphos)Ir(H)2{η1-o-S(C6H4)CHCH2} via C2–S bond cleavage; the latter compound is hydrogenated under mild conditions (2 bar H2, 80 °C) to the 2-ethylthiophenolate derivative (triphos)Ir(H)2{o-S(C6H4)Et} and under harsh conditions (30 bar H2, 160 °C) to free 2-ethylthiophenol and (triphos)IrH3.