The asymmetric use of S-pyroglutamic acid is based on its two differentiated carbonyls, the properties of which allow an extended derivatization on the 5-membered ring of the starting compound leading to a plethora of natural products, e.g., (−) domoic acid [6], the neurotoxin anatoxin-a [7], biologically interesting compounds, e.g., an inhibitor of angiotensin-converting enzyme (ACE) [8] for the treatment of hypertension as well as to chemical auxiliaries in asymmetric synthesis [9]. Here, ACE is linked to Hypertension.