Rh(III)-Catalyzed (4 + 1) Annulation of Pyrazol-3-ones with Alkynoates via Ortho-Alkenylation/Cyclization Cascade: Synthesis of Indazole-Fused Pyrazoles

J Org Chem. 2022 Sep 16;87(18):12109-12114. doi: 10.1021/acs.joc.2c01208. Epub 2022 Aug 25.

Abstract

A facile synthesis of novel indazole-fused pyrazoles from pyrazol-3-ones and alkynoate esters/amides via Rh(III)-catalyzed sequential C-H activation/ortho-alkenylation/intramolecular cyclization cascade is reported. The important characteristic of this method is that the resulting scaffold bearing quaternary carbon has been obtained through unusual [4 + 1] rather than expected [4 + 2] addition where alkynoate acts as a one-carbon unit.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amides
  • Carbon
  • Catalysis
  • Cyclization
  • Esters
  • Indazoles
  • Oxidation-Reduction
  • Pyrazoles
  • Rhodium*

Substances

  • Amides
  • Esters
  • Indazoles
  • Pyrazoles
  • Carbon
  • Rhodium