CHIRALITY CONTROL BY KINETIC PROTONATION: ENANTIOSELECTIVE SYNTHESES OF (+)-VELBANAMINE, (-)-ISOVELBANAMINE, AND (+)-CLEAVAMINE

Article abstract of DOI:10.1246/cl.1982.733

Optimal conditions for inversion of chirality at 2-position of the 2-alkyllactone(5) have been established.By utilizing the inversion method developed, three indole alkaloids, (+)-velbanamine(16), (-)-isovelbanamine(17), and (+)-cleavamine(18), have been synthesized from the chiral lactone(1) which has been previously used for the syntheses of the enantiomers of these alkaloids.