Copper-Mediated Single-Electron Approach to Indoline Amination: Scope, Mechanism, and Total Synthesis of Asperazine A

J Org Chem. 2022 Aug 5;87(15):9907-9914. doi: 10.1021/acs.joc.2c00923. Epub 2022 Jul 25.

Abstract

Pyrroloindolines bearing a C3-N linkage comprise the core of many biologically active natural products, but many methods toward their synthesis are limited by the sterics or electronics of the product. We report a single electron-based approach for the synthesis of this scaffold and demonstrate high-yielding aminations, regardless of electronic or steric demands. The transformation uses copper wire and isopropanol to promote the reaction. The broad synthetic utility of this heterogeneous copper-catalyzed approach to access pyrroloindolines, diketopiperazine, furoindoline, and (+)-asperazine is included, along with experiments to provide insight into the mechanism of this new process.

Publication types

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

MeSH terms

  • Amination
  • Catalysis
  • Copper*
  • Diketopiperazines
  • Electrons*
  • Indoles
  • Piperazines

Substances

  • Diketopiperazines
  • Indoles
  • Piperazines
  • asperazine
  • asperazine A
  • indoline
  • Copper