Electron spin resonance study of the fragmentation of some cyclic and acyclic dialkoxyalkyl radicals. The mechanism of 1,2-rearrangement of β-acyloxyalkyl radicals

Abstract

The di-t-butoxymethyl radical and a series of 1,3-dioxolanyl and 1,3-dioxanyl radicals have been generated and studied by e.s.r. spectroscopy in soulution. All of these radicals undergo β-scission under appropriate conditions, β-acyloxyalkyl radicals resulting from the 1,3-dioxolanyl radicals. The kinetics of β-scission of these dialkoxyalkyl radicals have been measured, and it is found that the di-t-butoxymethyl radical decomposes much more readily than the analogous cyclic 4,4,5,5-tetramethyldioxolanyl radical undergoes ring opening. The relevance of these results to the mechanism of vicinai rearrangement of β-acyloxyalkyl radicals is discussed. The rate constant for addition of the di-t-butoxymethyl radical to nitrosobutane is found to be about 10⁶ l mil^–1S^–1 at 40° in benzene.