Mechanochemistry Enabled Construction of Isoxazole Skeleton via CuO Nanoparticles Catalyzed Intermolecular Dehydrohalogenative Annulation

A dehydrohalogenative approach for isoxazole annulation by partnering β-vinyl halides and α-nitrocarbonyls under mechanochemical setting was accomplished. This chemistry is operative under the cooperative catalysis of cupric oxide nanoparticles (<50 nm) and DABCO. The key beneficial aspects of this protocol include: (i) broad substrate scope, (ii) no vigorous work-up, (iii) short reaction time, (iv) solvent-free condition, (v) commercial viability of substrates/reagents (vi) good chemical yields and selectivity. The other merit of this chemistry is the ease with which CuO can be recuperated and reused after the reaction with not much drop in catalytic activity for six runs. With no confinement to β-vinyl halides, the validated condition is also open to alkynes for isoxazole preparation, thereby establishing the broader utility of the current methodology. (Figure presented.).