An efficient copper(II)-catalyzed direct access to primary amides from aldehydes under neat conditions

A simple expeditious one-pot conversion of a wide assortment of aldehydes to corresponding primary amides in good to excellent yields has been accomplished employing hydroxylamine hydrochloride (1 mol equiv), sodium acetate (1.1 mol equiv), and copper sulfate pentahydrate (5 mol %) under neat conditions at 110 °C. The protocol based upon ligand-free copper (II)-catalysis avoids the use of relatively expensive late transition metal-based catalysts, and is performed under operationally simple conditions without any demanding procedure of isolation and purification of products.