High yield and greener C–H difluoromethylation reactions using copper iodide nanoparticles/boron nitride nanosheets as a versatile and recyclable heterogeneous catalyst

Abstract

Copper iodide (CuI) nanoparticles/boron nitride nanosheets (BNNSs) were prepared via an ultrasonication method and subsequently characterized. For the first time, these newly synthesized CuI/BNNS supports were used as heterogeneous catalysts for C–H difluoromethylation reactions, including the synthesis of heteroarenes and terminal alkynes. The versatility of the catalyst was demonstrated for the synthesis of diverse substituted difluoromethylated heteroarenes and terminal alkynes from electron-deficient and electron-rich groups, resulting in moderate to high yields (up to 91%). The reaction was carried out in a greener medium (cyrene instead of dimethylformamide and N-methyl-2-pyrrolidone) at room temperature using (difluoromethyl)trimethylsilane and 9,10-phenanthraquinone in the presence of the CuI/BNNS catalyst containing ∼3 wt% Cu and I. Notably, its activity was found to provide higher yield, shorter reaction time, and fewer usage of the catalyst, compared with commercial CuI catalysts. In addition, the CuI/BNNS catalyst could be easily recovered and recycled up to five times, with only a slight decrease (3%) in its catalytic activity, providing attractive features for chemical engineers to use this catalyst for the large-industrial scale synthesis of organic bioactive compounds involving C–H difluoromethylation reactions.