Breaking the Base Barrier: An Electron-Deficient Palladium Catalyst Enables the Use of a Common Soluble Base in C-N Coupling

J Am Chem Soc. 2018 Apr 4;140(13):4721-4725. doi: 10.1021/jacs.8b01696. Epub 2018 Mar 22.

Abstract

Due to the low intrinsic acidity of amines, palladium-catalyzed C-N cross-coupling has been plagued continuously by the necessity to employ strong, inorganic, or insoluble bases. To surmount the many practical obstacles associated with these reagents, we utilized a commercially available dialkyl triarylmonophosphine-supported palladium catalyst that facilitates a broad range of C-N coupling reactions in the presence of weak, soluble bases. The mild and general reaction conditions show extraordinary tolerance for even highly base-sensitive functional groups. Additionally, insightful heteronuclear NMR studies using 15N-labeled amine complexes provide evidence for the key acidifying effect of the cationic palladium center.

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

  • Carbon / chemistry*
  • Catalysis
  • Electrons*
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Nitrogen / chemistry*
  • Palladium / chemistry*
  • Solubility

Substances

  • Palladium
  • Carbon
  • Nitrogen