Ethylacetoacetate tagged basic imidazolium salt: multi-task in CuI nanoparticle catalyzed amination of aryl halides

Copper catalyzed reactions suffer from harsh conditions of high temperature, high pressure, over-stoichiometric amount of copper reagents and use of expensive ligands. In an attempt to develop a mild, efficient and reusable system for copper catalyzed reactions, ethylacetoacetate was doped into ionic liquid (IL) by tagging it with imidazolium cation stabilized by a counter hydroxide or acetate anion (4a and 4b). The novel ligand-anchored ILs demonstrated high efficiency in generation and stabilization of uniformly dispersed Cu(I)I nanoparticles with particle size in range 9-12 nm. Further, the catalytic system provided an efficient route to amination of aryl iodides, bromides and the less reactive chlorides under mild conditions with very low catalyst loading of only 2 mol % to yield primary aryl amines selectively. Furthermore, the reaction allowed easy isolation of products with recovery of ionic liquid containing an intact built-in ligand and base combination for further reuse.

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