Copper-Catalyzed Cross-Coupling of Benzylic C-H Bonds and Azoles with Controlled N-Site Selectivity

J Am Chem Soc. 2021 Sep 15;143(36):14438-14444. doi: 10.1021/jacs.1c07117. Epub 2021 Aug 31.

Abstract

Azoles are important motifs in medicinal chemistry, and elaboration of their structures via direct N-H/C-H coupling could have broad utility in drug discovery. The ambident reactivity of many azoles, however, presents significant selectivity challenges. Here, we report a copper-catalyzed method that achieves site-selective cross-coupling of pyrazoles and other N-H heterocycles with substrates bearing (hetero)benzylic C-H bonds. Excellent N-site selectivity is achieved, with the preferred site controlled by the identity of co-catalytic additives. This cross-coupling strategy features broad scope for both the N-H heterocycle and benzylic C-H coupling partners, enabling application of this method to complex molecule synthesis and medicinal chemistry.

Publication types

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

MeSH terms

  • Azoles / chemical synthesis*
  • Benzyl Compounds / chemistry
  • Catalysis
  • Copper / chemistry
  • Indans / chemistry
  • Molecular Structure
  • Oxidants / chemistry
  • Oxidation-Reduction
  • Sulfonamides / chemistry

Substances

  • Azoles
  • Benzyl Compounds
  • Indans
  • Oxidants
  • Sulfonamides
  • N-fluorobenzenesulfonimide
  • Copper