Asymmetric synthesis of N-allylic indoles via regio- and enantioselective allylation of aryl hydrazines

Nat Commun. 2015 Jul 3:6:7616. doi: 10.1038/ncomms8616.

Abstract

The asymmetric synthesis of N-allylic indoles is important for natural product synthesis and pharmaceutical research. The regio- and enantioselective N-allylation of indoles is a true challenge due to the favourable C3-allylation. We develop here a new strategy to the asymmetric synthesis of N-allylic indoles via rhodium-catalysed N-selective coupling of aryl hydrazines with allenes followed by Fischer indolization. The exclusive N-selectivities and good to excellent enantioselectivities are achieved applying a rhodium(I)/DTBM-Segphos or rhodium(I)/DTBM-Binap catalyst. This method permits the practical synthesis of valuable chiral N-allylated indoles, and avoids the N- or C-selectivity issue.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkadienes / chemistry*
  • Allyl Compounds / chemical synthesis*
  • Benzoxazines / chemical synthesis
  • Catalysis
  • Hydrazines / chemistry*
  • Indoles / chemical synthesis*
  • Morpholines / chemical synthesis
  • Naphthalenes / chemical synthesis
  • Plant Extracts / chemical synthesis
  • Rhodium / chemistry
  • Stereoisomerism
  • Vincamine / chemical synthesis

Substances

  • Alkadienes
  • Allyl Compounds
  • Benzoxazines
  • Hydrazines
  • Indoles
  • Morpholines
  • Naphthalenes
  • Plant Extracts
  • Yuremamine
  • propadiene
  • (3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone
  • Vincamine
  • Rhodium