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 KOBu^t 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.