An Useful Synthetic Method for 3-Substituted δ-Lactones. Synthesis of (+/-)-Secocrispiolide

Article abstract of DOI:10.1246/bcsj.64.1479

2-Phenylthio-2-penten-5-olide (1) acted as a reactive Michael acceptor toward some typical carbon nucleophiles to give 3-substituted 2-phenylthio-5-pentanolides (2) which were convertible both to 3-substituted 5-pentanolides by reductive desulfurization and to 3-substituted 2-penten-5-olides by sulfenic acid syn elimination of the sulfoxides 4 derived from 2.The Pummerer rearrangement of 4 provided 3-substituted 2-phenylthio-2-penten-5-olides and/or 2-hydroxy-2-penten-5-olides. (+/-)-Secocrispiolide was synthesized via the adduct obtained by the Michael reaction of 1 with the Grignard reagent prepared from 2,6-dimethylbenzyl bromide and magnesium.