Abstract: The solvolyses of CH3CH2CH (OTs) CH3, CH3CH2CD (OTs) CD3 (111) and CD3CD2CH (OTs) CH3 (XIII) have been studied in CF3COOH and CF3COOD. The product distributions and solvolysis rates are consistent with the intermediacy of a hydrogen-bridged 2-butyl cation. The ratio of the solvolysis rates of I11 to XI11 is 1.1-1.2 which is consistent with anchimeric assistance by a 8-H on C3. The rate of additions of CF3COOH to 2-butene ...