With the optimized conditions in hand, various amines, including complex structures were tested for hydrogen isotope exchange (HIE). All tested compounds shown in Fig. gave good to excellent yields with excellent selectivity (> 95%) for the α-amino ester position. Substrates bearing an N-methyl, ethyl, and propyl substituent, gave the respective product in high yields with a selectivity of up to 99% for the deuterium incorporation (1-3). The same is true for cyclic amines (4) even in presence of a benzylic position. Sterically hindered amines underwent an efficient deuterium labelling as well . Opposed to a classical deprotonation with harsh bases, the here presented method offers a high functional group tolerance, with functionalities such as carboxylic esters, boronic esters (8), amides , and nitriles remaining inert. A benzene ring can be placed between the α-amino position and the electronwithdrawing ester functionality , yet the deuterium incorporation decreases in this case. Replacing the PMP protecting group with a different aromatic substituent like toluene is possible as well . In addition to tertiary amines, secondary amines (R2NH) are viable substrates, too . Notably, even electron-deficient secondary amines, bearing potential protic hydrogen are suitable substrates using this method (14-16).