Novel Synthesis of Pyrrolidinones by Cobalt Carbonyl Catalyzed Carbonylation of Azetidines. A New Ring-Expansion-Carbonylation Reaction of 2-Vinylazetidines to Tetrahydroazepinones

Article abstract of DOI:10.1021/ja00201a040

Pyrrolidinones can be synthesized in high yields and regioselectivity by the cobalt carbonyl catalyzed carbonylation of azetidines.For 2-substituted azetidines (alkyl, aryl, CH2OH, CH2OR, CH2OCOR, and COOR), carbonyl insertion occurs in the more or less substituted ring carbon-nitrogen bond depending on the kind of substituent group and on the reaction temperature.In the case of 2-vinylazetidines, ring expansion and carbonylation affords seven-membered-ring tetrahydroazepinones.Good functional group tolerance was observed in these reactions.