Stereocontrolled Synthesis of (±)-Melokhanine E via an Intramolecular Formal [3 + 2] Cycloaddition

Org Lett. 2020 Jan 17;22(2):714-717. doi: 10.1021/acs.orglett.9b04546. Epub 2020 Jan 7.

Abstract

A convergent sequence to access the indole alkaloid (±)-melokhanine E in 12-steps (8-step longest linear sequence) and an 11% overall yield is reported. The approach utilizes two cyclopropane moieties as reactive precursors to a 1,3-dipole and imine species to enable stereoselective construction of the core scaffold through a formal [3 + 2] cycloaddition. The natural product was evaluated for its antimicrobial activity based on isolation reports; however, no activity was observed. The reported efforts serve as a synthetic platform to prepare an array of alkaloids bearing this core structural motif.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cycloaddition Reaction
  • Cyclopropanes / chemistry*
  • Imines / chemistry*
  • Molecular Structure
  • Secologanin Tryptamine Alkaloids / chemical synthesis*
  • Secologanin Tryptamine Alkaloids / chemistry
  • Stereoisomerism

Substances

  • Cyclopropanes
  • Imines
  • Secologanin Tryptamine Alkaloids
  • cyclopropane