Functionalization of N,N′- disubstituted alanylglycine anhydrides under radical conditions is described. The radical (7), generated ( i ) from reactions of N,N'- disubstituted alanylglycine anhydrides with N- bromosuccinimide , and (ii) from related bromo compounds by reaction with tributyltin deuteride , undergoes carbon-bromine and carbon-deuterium bond formation with moderate to high diastereoselectivities depending on the N- substituents present.