Regioselective Direct C−H Bond (Hetero)arylation of Thiazoles Enabled by a Novel Iminopyridine-Based α‐Diimine Nickel(II) Complex Evaluated by DFT Studies.

Abstract

Direct C−H bond arylation is a highly effective method for synthesizing arylated heteroaromatics. This method reduces synthetic steps and minimizes the formation of impurities. We report an air and moisture-stable iminopyridine-based α-diimine nickel (II) complex for direct C5-H bond arylation of thiazole derivatives. Under low catalyst loading and performing the reactions at lower temperatures (80 °C) under aerobic conditions, we produced mono- and diarylated thiazole units. Competition experiments and density functional theory calculations (DFT) revealed that the mechanism of C−H activation in 4-methylthiazole involves electrophilic aromatic substitution.

Regioselective Direct C–H Bond Heteroarylation of Thiazoles Enabled by an Iminopyridine-Based α-Diimine Nickel(II) Complex Evaluated by DFT Studies

“…In an attempt to understand how the nickel catalytic system works on direct arylation of thiazole, DFT calculations were done. 32 ■ RESULTS AND DISCUSSION Synthesis and Characterization of the α-Diimine Nickel(II) Complex. The syntheses of the complexes and ORTEP diagrams are shown in Scheme 1.…”