Light-Induced Synthesis of Tricyclic Thiolane Derivatives from 2(5H)-Thiophenones via Consecutive Radical Ring Closure

Article abstract of DOI:10.1002/hlca.19880710225

Two α,β-unsaturated thiolactones, 5-(2-propynyl)-2(5H)-thiophenone (5) and 3,5-di(2-propenyl-2(5H)-thiophenone (6), were newly synthesized.Irradiation (λ = 300 nm) of 5 in MeOH containing cyclopentene afforded a 3:1 mixture of diastereoisomeric methyl 7-thiatricyclo<6.4.0.0^2,6>dodec-10-ene-12-carboxylates (8a/8b), while irradiation of 6 in MeOH saturated with 2-methylpropene gives a 3:2 mixture of diastereoisomeric methyl 3,3,9-trimethyl-5-thiatricyclo<6.2.1.0^2,6>undecane-1-carboxylates (10a/10b).