Copper-catalyzed radical cyclization to access 3-hydroxypyrroloindoline: biomimetic synthesis of protubonine A

Org Lett. 2014 Jun 20;16(12):3276-9. doi: 10.1021/ol501287x. Epub 2014 Jun 12.

Abstract

An unprecedented copper-catalyzed intramolecular radical cyclization was developed for the synthesis of 3-hydroxypyrroloindoline skeletons in excellent yields. The 3-hydroxyl group was introduced by trapping the radical intermediate with molecular oxygen or TEMPO. This process represents a unique radical oxidation pathway for tryptamine/tryptophan derivatives and allows a rapid biomimetic synthesis of natural product protubonine A.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaloids / chemical synthesis*
  • Alkaloids / chemistry
  • Biomimetics
  • Catalysis
  • Copper / chemistry*
  • Cyclization
  • Diketopiperazines / chemical synthesis*
  • Diketopiperazines / chemistry
  • Indoles / chemical synthesis
  • Molecular Structure
  • Oxidation-Reduction
  • Stereoisomerism
  • Tryptophan

Substances

  • Alkaloids
  • Diketopiperazines
  • Indoles
  • protubonine A
  • Copper
  • Tryptophan