A novel acenaphthoimidazolyidene oxazolinic palladium complex and its efficient catalysis in Suzuki-Miyaura cross-coupling reactions of N-acyl-glutarimides via N-C cleavage

Herein, we synthesized a new Pd-N-heterocyclic carbene (Pd-NHC) complex that featured an acenaphthoimidazolylidene (AnIm) skeleton and 2-phenyl-2-oxazoline. This catalyst exhibited extremely high efficiency in Suzuki-Miyaura couplings between N-acyl-glutarimides and organoboronic acids, affording various aryl ketones in excellent yields with a broad substrate scope and wide functional group compatibility. Notably, the reactions were completed in just 5 hours with only 0.5 mol% of catalyst. In addition, this catalytic system also enables the efficient synthesis of functional molecular intermediates. The catalyst, designed through the synergistic integration of a throw-away ligand and an extended conjugated NHC system, further demonstrates its remarkable potential.

A Second-Generation Palladacycle Architecture Bearing a N-Heterocyclic Carbene and Its Catalytic Behavior in Buchwald–Hartwig Amination Catalysis

Palladacyclic architectures have been shown as versatile motifs in cross-coupling reactions. NHC-ligated palladacycles possessing unique electronic and steric properties have helped to stabilize the catalytically active species and provide additional control over reaction selectivity. Here, we report on a synthetic protocol leading to palladacycle complexes using a mild base and an environmentally desirable solvent, with a focus on complexes bearing backbone-substituted N-heterocyclic carbene ligands. The readily accessible complexes exhibit high catalytic activity in the Buchwald–Hartwig amination. This is achieved using low catalyst loading and mild reaction conditions in a green solvent.