The β-(acyloxy)alkyl radical rearrangement revisited

A β-(acyloxy)alkyl radical precursor, containing a carboxylate residue suitably placed for the trapping of any intermediate alkene radical cations, has been constructed. In nonpolar solutions the probe, in the form of either the free acid or its tetrabutylammonium salt, undergoes the typical rearrangement reaction with no evidence of trapping, leading to the conclusion that the reaction is either concerted or that collapse of any intermediate contact ion pair is so rapid as to preclude the possibility of trapping.Key words: radical, rearrangement, contact ion pair.