Merging Visible Light Photocatalysis and l-/d-Proline Catalysis: Direct Asymmetric Oxidative Dearomatization of 2-Arylindoles To Access C2-Quaternary Indolin-3-ones

Org Lett. 2020 Feb 7;22(3):1076-1080. doi: 10.1021/acs.orglett.9b04613. Epub 2020 Jan 24.

Abstract

A mild and effective method for asymmetric synthesis of C2-quaternary indolin-3-ones directly from 2-arylindoles by combining visible light photocatalysis and organocatalysis is described. In this reaction, 2-substituted indoles undergo photocatalyzed oxidative dearomatization, followed by an organocatalyzed asymmetric Mannich reaction with ketones or aldehydes. Products with opposite configurations are easily obtained in satisfactory yields with excellent enantio- and diastereoselectivity by employing readily available l- and d-proline as chiral organocatalysts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Indoles / chemistry*
  • Light*
  • Molecular Structure
  • Oxidation-Reduction
  • Photochemical Processes
  • Proline / chemistry*
  • Stereoisomerism

Substances

  • Indoles
  • Proline