The radical translocation reactions in N,N-disubstituted acetamides 10a, 14a-d and trifluoroacetamides 10b, 14e-f have been studied by deuteration experiments with n-Bu3SnD. The intramolecular hydrogen atom transfer from the N-alkyl side chain to the aryl radical takes place through competing 6-, 7-, 8-membered ring transition states.