Rearrangements of Trihalomethyl Ketones

Trihalomethyl ketones have been prepared and their reactivity under basic conditions was investigated in terms of competition between 1,2- vs. 1,3-elimination and nucleophilic substitution. Favorskii rearrangement was the preferred process, but in those cases where electronic or steric effects were present, nucleophilic substitution became dominant. No evidence of ketene formation was detected. The mechanism of formation of the various rearrangement products is discussed.