Cascades synthesis of N-aryl oxindole nitrone derivatives using isatine oximes and arylboronic acids catalyzed by copper acetate under mild conditions

Cu-catalysis was employed to create numerous (E)-5-bromo-N-aryl oxindole nitrones with satisfactory to excellent coupling efficiencies. This process involved the reaction of N-unprotected 5-bromoisatin-3-oximes with aryl-boronic acids under moderately reactive conditions. Remarkably, the reaction exhibited tolerance towards various aryl-boronic acids containing diverse functional sensitivity subgroups (73% to 97% yields and 2 to 6 h). Extensive research has demonstrated that the (C=O) group present in 5-bromoisatin-3-oximes can serve as an inhibitory molecule or ligand, playing a crucial role in the generation of (E) oxindole nitrones.