Studies in Biomimetic Alkaloid Syntheses. 12. Enantioselective Total Syntheses of (-)- and (+)-Vincadifformine and of (-)-Tabersonine

Article abstract of DOI:10.1021/jo00207a002

The (-) and (+) enantiomers of vincadifformine (1) were obtained with <*> 98percent ee and <*> 97percent ee, respectively (before purification), from the two enantiomers of epichlorhydrin.This synthetic scheme is based on generation and cyclization of the enantiomeric (hydroxymethyl)norsecodine intermediates 3a,b.By an alternative synthetic route, passing through (14S)-14-hydroxy-Δ^20,21-secodine (14), (-)-tabersonine (18b) was obtained with <*> 99percent ee.