Enantioselective total syntheses of (+)-arborescidine A, (-)-arborescidine B, and (-)-arborescidine C

J Org Chem. 2004 Feb 20;69(4):1283-9. doi: 10.1021/jo035165f.

Abstract

Described are the first enantioselective total syntheses of (+)-arborescidine A ((+)-1), (-)-arborescidine B ((-)-2), and (-)-arborescidine C ((-)-3), via routes that proceeded in five steps and 50% overall yield, eight steps and 61% overall yield, and nine steps and 51% overall yield, respectively, from 6-bromotryptamine (7). The syntheses feature the use of the Noyori catalytic asymmetric hydrogen-transfer reaction to introduce chirality in dihydro-beta-carbolines 6 and 8. On the basis of an ample precedent from Noyori's work, the reduction produces dihydro-beta-carbolines, and ultimately the natural products, possessing the R absolute configuration. The synthetic arborescidines displayed optical rotations that were opposite in sign those of the natural products, thereby supporting the S configuration for natural arborescidines A (1) and B (2) and the (3S,17S) configuration for natural arborescidine C (3). Our results are in agreement with the initial stereochemical assignment by Païs and co-workers, and are counter to their recently revised assignment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkaloids / chemical synthesis*
  • Alkaloids / chemistry
  • Carbohydrate Conformation
  • Indole Alkaloids
  • Indoles / chemical synthesis*
  • Indoles / chemistry
  • Molecular Structure
  • Stereoisomerism

Substances

  • Alkaloids
  • Indole Alkaloids
  • Indoles
  • arborescidine A
  • arborescidine B
  • arborescidine C