Summary The acetolysis (SO') of the 4-bromobenzenesulfonates given in Scheme 6 were investigated in regard to determine the allyVmethy1 migratory aptitudes in the secondary carbenium ion a (Scheme 24). In all cases olefins (about 80%) and acetates (about 20%) were formed which can be derived from the rearranged tertiary carbenium ions b (being formed by allyl group migration) and c (being formed by methyl group migration).