The rearrangement of (R)-N-isobutenyl-N-methyl-benzylamine-a-d was thermally effected to give (R)-2, 2-dimethyl-3-phenyl-propanal-3-d with over-all retention of configuration ofthe migrating terminus in 91 % asymmetric yield. The stereochemical outcome in the present benzyl migration unequivocally established the mechanism to be the sequential N-alkylation, retrogressive dissociation and C-alkylation, with two Walden inversions involved in the process
