Enantiospecific Construction of Quaternary Carbon Center via Intramolecular 1,3-Dipolar Cycloaddition. A New Route to Natural (-)-Mesembrine from (S)-O-Benzylglycidol

Article abstract of DOI:10.1246/cl.1990.1239

Thermolysis of the aziridine ester, obtained from (S)-O-benzylglycidol, afforded the pyrrolidine lactone bearing a quaternary carbon center stereo-specifically in a good yield via intramolecular cycloaddition of the 1,3-dipole.The adduct (11) could be converted into natural (-)-mesembrine, the major alkaloid of Sceletium namaquense, and its N-demethyl derivative via a 8 step sequence of reactions.