Enantioselective BINOL-phosphoric acid catalyzed Pictet-Spengler reactions of N-benzyltryptamine

J Org Chem. 2008 Aug 15;73(16):6405-8. doi: 10.1021/jo8010478. Epub 2008 Jul 11.

Abstract

Optically active tetrahydro-beta-carbolines were synthesized via an ( R)-BINOL-phosphoric acid-catalyzed asymmetric Pictet-Spengler reaction of N-benzyltryptamine with a series of aromatic and aliphatic aldehydes. The tetrahydro-beta-carbolines were obtained in yields ranging from 77% to 97% and with ee values up to 87%. The triphenylsilyl-substituted BINOL-phosphoric acid proved to be the catalyst of choice for the reaction with aromatic aldehydes. For the aliphatic aldehydes, 3,5-bistrifluoromethylphenyl-substituted BINOL-phosphoric acid was identified as the best catalyst.

MeSH terms

  • Aldehydes / chemistry
  • Benzyl Compounds / chemistry
  • Carbolines / chemical synthesis*
  • Carbolines / chemistry
  • Catalysis
  • Naphthols / chemistry*
  • Oxidation-Reduction
  • Phosphoric Acids / chemistry*
  • Stereoisomerism
  • Tryptamines / chemistry*

Substances

  • Aldehydes
  • BINOL, naphthol
  • Benzyl Compounds
  • Carbolines
  • Naphthols
  • Phosphoric Acids
  • Tryptamines