N-ARYLATION OF TERTIARY AMINES UNDER MILD CONDITIONS

Quaternary ammonium salts have countless uses, such as phase-transfer catalysts and anion-exchange membranes, and constitute biologically relevant functional groups playing important roles in alkylation reactions and in natural products. Few examples of nucleophilic aromatic substitutions by tertiary amines are found in the literature, and those demand harsh reaction conditions and electron poor reagents. We describe the use of electrophilic aryls to produce the intended products under mild conditions. However, some of these reactive species tend to undergo competitive Friedel-Crafts additions, limiting the selectivity of the reaction. Selective reactions with good yields were obtained when using benzyne electrophiles to produce the intended products under mild conditions. We describe the reactivity of different tertiary amines and a broad scope of benzynes.