Epoxides and aziridines are strained three-membered heterocycles. Their synthetic utility lies in the fact that they can be ring-opened with a broad range of nucleophiles with high or often complete stereoselectivity and regioselectivity and that 1,2-difunctional ring-opened products represent common motifs in many organic
molecules of interest. As a result of their importance in synthesis, the preparation of epoxides and aziridines has been of considerable interest and many methods have been developed to date. Most use alkenes as precursors, these subsequently being oxidized. An alternative and complementary approach utilizes aldehydes
and imines. Advantages with this approach are: i) that potentially hazardous oxidizing agents are not required, and ii) that both C–X and C–C bonds are formed, rather than just C–X bonds
This review summarizes the best asymmetric methods for preparing epoxides nd aziridines from aldehydes (or ketones) and imines
