Efficient total syntheses of (±)-vincadifformine and (−)-tabersonine

Stereocontrolled biomimetic total syntheses of the title compounds art: described. Our syntheses feature a highly efficient preparation of the key intermediate II using our novel indole synthesis methodology. A novel amine protecting protocol hy means of 2,4-dinitrobenzenesulfonamides has been developed to ensure the formation of the elusive secodine (3) as well as secodine-type intermediate (4) under very mild conditions. (C) 1999 Elsevier Science Ltd. All rights reserved.