摘要:
The systematics of the gamma-scission reactions of beta-peroxyalkyl radicals to yield epoxides have been extended to include variations in the degree of alkylation at the alpha- and beta-carbon atoms and in the nature of the departing alkoxyl radical. The ratios of geometrically isomeric epoxides so produced have been shown to be dependent upon the steric bulk of the C(alpha)- and C(beta)-substituents but rather independent of the nature of the departing alkoxyl radical. The relative importance of 1,5-H atom transfer in beta-peroxyalkyl radicals has been considered and some evidence for its occurrence adduced. The relevance of these findings to published data for alkene autoxidation is discussed in terms of two competing pathways, in which, it is suggested, steric factors determine the outcome.