Novel synthesis of 3-carboxamidolactam derivatives via palladium-catalysed aminocarbonylation

Abstract

Aminocarbonylation of alkenyl and (hetero)aryl iodides using medium-sized 3-aminolactams as N-nucleophiles was carried out in the presence of in situ palladium(0) catalysts. While the iodoalkenes were converted to the corresponding carboxamide under mild reaction condition (1 bar of CO, 50 °C) by using Pd(OAc)2/PPh3 catalysts, the iodobenzene shown decreased reactivity (39% conversion after 2 days) under the similar reaction conditions in the presence of 3-aminoazepan-2-one. The reactivity of iodobenzene and other iodo(hetero)aromatic substrates was increased with 3-aminoazepan-2-one under high (40 bar) carbon monoxide pressure, but the chemoselectivity was shifted towards the 2-ketocarboxamides formed via double carbon monoxide insertion (except 2-iodopyridine). Changing triphenylphosphine to Xantphos, the expected carboxamides were chemoselectively formed in all cases when iodo(hetero)aryl substrates were used in the presence of all of the three 3-aminolactams under mild reaction conditions. The products synthesized in the reactions mentioned above were isolated in moderate to high yields.