Asymmetric Synthesis of three and four membered ring heterocycles

Small heterocyclic rings constitute systems of central importance in theoretical, synthetic organic, bioorganic, andmedicinal chemistry, and in particular aziridines and azirines are very useful and interesting systems as they occur in a number of natural and biologically active substances and as they are useful building blocks and versatile synthetic intermediates. Therefore, the development of efficient and stereoselective methods for synthesis and elaboration of aziridines is an inviting ongoing challenge [1]. Very often, stereogenic centers within such strained heterocycles can be used to direct the stereochemical outcome of subsequent transformations.