Heterocyclic synthesis three-membered thiirane rings

This chapter concerns the net conversion of a C =X ir-bond (X = O and N) to various three-membered ring heterocycles. The most common such process is the conversion of an aldehyde or ketone to a homologous epoxide. These reactions will be discussed along with the analogous process which takes place on imines and related compounds. Additionally, methods to effect the addition of elements other than carbon across either unsaturated system will considered. The synthesis of thiiranes by the addition of carbon across the C—S rr-bond is the subject of a recent comprehensive review and will not be covered here. 

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