CARBON-CARBON BOND FORMATION BETWEEN ENONE AND ESTER CARBONYL GROUP INDUCED BY SAMARIUM DIIODIDE

摘要

Reductive cyclization of methyl, TBDMS, pentafluorophenyl, trichloroethyl, or MOM ester of 4-(2-methyl-6-oxocyclohex-1-enyl)butanoic acid was attempted by treating with SmI2, with or without additive (MeOH, H2O, HMPA, NiI2), to establish whether Claisen-type carbon-carbon bond formation occurred. Methyl ester afforded dimeric products, while trichloroethyl and MOM ester yielded hexahydronaphthalenediones. Pentafluorophenyl ester gave a spiro compound. It is thought that all these products were formed through an anionic intermediate produced by two-electron reduction of the enone moiety by SmI2.