Copper(I) Oxide Nanoparticles in Glycerol: A Convenient Catalyst for Cross-Coupling and Azide-Alkyne Cycloaddition Processes

Well-defined and small copper(I) oxide nanoparticles stabilised by poly(vinylpyrrolidone) in neat glycerol have been synthesised under a dihydrogen atmosphere. The as-prepared material has been successfully applied in Cheteroatom couplings and azide-alkyne cycloadditions to give the desired products selectively with isolated yields higher than 90%. Different amines have been used in the CN couplings, which include aqueous ammonia, that led to the synthesis of anilines. Mono-1,4-disubstituted triazoles and also bis- and tris(triazoles) have been obtained by the regioselective Cu-catalysed Huisgen reaction, which comprises the synthesis of dissymmetrical substituted bis(triazoles). The catalytic glycerol phase could be recycled at least ten times and keeps its activity and selectivity. Moreover this versatile catalyst allowed tandem cycloaddition/CN coupling processes to give the corresponding polyfunctional products in a high global yield without the isolation of intermediates.