Unless you've studied chemistry in college, it's unlikely you've come across the name aziridine. An organic compound with the molecular formula, C2H4NH, aziridines are well-known among medicinal chemists, who make use of the compound to prepare pharmaceutical drugs such as Mitomycin C, a chemotherapeutic agent known for its anti-tumor activity. Specifically, aziridines are what chemists call enantiomers—molecules that are mirror images of each other and cannot be superposed on one another. A peculiarity with enantiomers is that the biological activity of one is different from its mirror image and only one of them is desirable for making drugs. Chemists, therefore, regularly opt for asymmetric or enantioselective synthesis techniques that yield the desired enantiomer in greater amounts.