Certain reactions involving α-amino acids carry the risk of concomitant racemization, especially when the α-carboxy group has to be activated in the presence of bases. So a synthetic strategy avoiding racemization-prone conversions has to be developed.

If the risk of racemization exists (e.g. during loading of resins), the optical purity is controlled after performing the reaction.

The optical rotation is determined only if reference values can be taken from the literature.