| Zusammenfassung: | <p>This work describes developments in new azetidine and azetine chemistry; specifically, methods developed for the introduction of functionality α- to nitrogen in both ring systems, with additionally <em>in situ</em> formation of the latter system, from azetidine substrates.</p> <p>Chapter 1 discusses the growing importance of azetidines, and the current methods available for making substituted azetidines by ring formation. Further discussion comprises of current sp<sup>3</sup> C–H activation approaches α- to nitrogen in heterocyclic compounds as potential methods for sp<sup>3</sup> C–H activation on azetidines to give substituted azetidines. Previous work by the Hodgson group in this area is detailed.</p> <p>Chapter 2 describes the advance made towards 2,3-disubstituted azetidines using the thiopivaloyl protecting/activating group, where the latter plays a key role. Optimisation, scope, selectivity and mechanistic insight into the α-deprotonation–electrophile trapping of a 3-hydroxy azetidine system is discussed, which successfully gives access to a range of 3-hydroxy-2-substituted azetidines. Preliminary investigations with 3-alkyl-2-substituted azetidines are also described.</p> <p>Chapter 3 describes the development of a straightforward protocol to make 2-substituted-2- azetines, a rarely studied and difficult to access 4-membered azacycle subclass, from readily accessible azetidine starting materials using α-deprotonation–<em>in situ</em> elimination followed by further α-lithiation–electrophile trapping. Extension of this methodology by transmetallation from the intermediate organolithium to the organocuprate, resulting in greater electrophile scope, is also described.</p>
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