Al2O3 promoted mechanochemical nucleophilic aromatic substitution

An auxiliary mediated solventless mechanochemical methodology for the nucleophilic aromatic substitution of aryl fluorides by nitrogen nucleophiles without the aid of any base has been developed. The excellent affinity of Al2O3 for hydrogen fluoride is the key for this process. Thanks to the use of Al2O3 as a milling auxiliary yields of up to 99% were achieved, and the easily processable crude derived from the milling jar allowed a simple and fast work-up procedure, making this method very attractive.