Login / Signup

Dual-Ligand Catalyst for the Nondirected C-H Olefination of Heteroarenes.

Guangrong MengZhen WangHau Sun Sam ChanNikita ChekshinZhen LiPeng WangJin-Quan Yu
Published in: Journal of the American Chemical Society (2023)
Pd(II)-catalyzed nondirected C-H functionalization of heteroarenes is a significant challenge for the following reasons: poor reactivity of electron-deficient heterocycles and the unproductive coordination of Lewis basic nitrogen atoms. Existing methodologies using palladium catalysis often employ a large excess of heterocycle substrates to overcome these hurdles. Despite recent advances in nondirected functionalization of arenes that allow them to be used as limiting reagents, the reaction conditions are incompatible with electron-deficient heteroarenes. Herein we report a dual-ligand catalyst that enables Pd(II)-catalyzed nondirected C-H olefination of heteroarenes without using a large excess of substrate. In general, the use of 1-2 equiv of substrates was sufficient to obtain synthetically useful yields. The reactivity was rationalized by the synergy between two types of ligands: a bidentate pyridine-pyridone ligand promotes C-H cleavage; the monodentate heterocycle substrate acts as a second ligand to form a cationic Pd(II) complex that has high affinity for arenes. The proposed dual-ligand cooperation is supported by a combination of X-ray, kinetics, and control experiments.
Keyphrases
  • room temperature
  • reduced graphene oxide
  • computed tomography
  • highly efficient
  • magnetic resonance imaging
  • magnetic resonance
  • high resolution