Sulfonate Versus Sulfonate: Nickel and Palladium Multimetallic Cross-Electrophile Coupling of Aryl Triflates with Aryl Tosylates

J Am Chem Soc. 2020 Jun 17;142(24):10634-10640. doi: 10.1021/jacs.0c04670. Epub 2020 Jun 8.

Abstract

While phenols are frequent and convenient aryl sources in cross-coupling, typically as sulfonate esters, the direct cross-Ullmann coupling of two different sulfonate esters is unknown. We report here a general solution to this challenge catalyzed by a combination of Ni and Pd with Zn reductant and LiBr as an additive. The reaction has broad scope, as demonstrated in 33 examples (65% ± 11% average yield). Mechanistic studies show that Pd strongly prefers the aryl triflate, the Ni catalyst has a small preference for the aryl tosylate, aryl transfer between catalysts is mediated by Zn, and Pd improves yields by consuming arylzinc intermediates.

Publication types

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

MeSH terms

  • Catalysis
  • Mesylates / chemistry*
  • Molecular Structure
  • Nickel / chemistry*
  • Palladium / chemistry*
  • Sulfonic Acids / chemistry*
  • Tosyl Compounds / chemistry*
  • Zinc / chemistry

Substances

  • Mesylates
  • Sulfonic Acids
  • Tosyl Compounds
  • Palladium
  • Nickel
  • Zinc
  • trifluoromethanesulfonic acid