A COMPARISON OF SKELETAL REARRANGEMENT REACTIONS OF EVEN-ELECTRON ANIONS IN SOLUTION AND IN THE GAS-PHASE

There is significant correspondence between certain skeletal rearrange ment processes of close-shell organic anions in the condensed and gas phases. Examples of such correspondence include the acyloin, acyl oxya cetate, anionic oxy Cope, anionic Wolff, benzilic acid, Dieckmann, Los sen, Smiles and Wittig rearrangements. In contrast, there are some rea rrangements observed in the condensed phase, which are either minor or do not occur at all in the gas phase. The Favorskii, Tiemann and Carr oll rearrangements fall into this category. Finally, there are some ga s phase rearrangements which have no condensed phase analogy: for exam ple the negative ion pinacol/pinacolone and Beckmann rearrangements. T hese, and related processes are discussed in this Review.