In order to have better control of the quality of the chiral amine 11 used in this work, we decided to synthesize this material in-house. Synthesis of 11 is described in the literature making use of diverse approaches with D/L-proline as the starting point. Distillation of the chiral amine 11 prior to its use in the BA reaction was adopted as standard procedure. This way, not only the moisture content could be reduced, but also the removal of inorganic salts in the crude material. Additionally, storing the pure fraction of the distilled amine 11 over molecular sieves and inert atmosphere is recommended.