2-Bromo-6-isocyanopyridine as a Universal Convertible Isocyanide for Multicomponent Chemistry

The development of 2-isocyanopyridines as novel convertible isocyanides for multicomponent chemistry is reported. Comparison of 12 representatives of this class revealed 2-bromo-6-isocyanopyridine as the optimal reagent in terms of stability and synthetic efficiency. It combines sufficient nucleophilicity with good leaving group capacity of the resulting amide moiety under both basic and acidic conditions. To demonstrate the practical utility of this reagent, an efficient two-step synthesis of the potent opioid carfentanil is presented.