Rearrangements of trihalomethyl ketones

Trihalomethyl ketones have been prepared and their reactivity under basic c onditions was investigated in terms of competition between 1,2- vs. 1,3-eli mination and nucleophilic substitution. Favorskii rearrangement was the pre ferred process, but in those cases where electronic or steric effects were present, nucleophilic substitution became dominant. No evidence of ketene f ormation was detected. The mechanism of formation of the various rearrangem ent products is discussed. (C) 2000 Elsevier Science Ltd. All rights reserv ed.