Azetidines: New Tools for the Synthesis of Nitrogen Heterocycles

Compared to other nitrogen heterocycles such as aziridines, pyrrolidines, or piperidines, the chemistry of azetidines is Much less developed, probably because of their limited availability. In this account, recent synthetic routes to these strained heterocycles starting front readily available enantiomerically pure starting compounds will be detailed. The ring strain in these heterocycles makes them excellent candidates for nucleophilic ring-opening or ring-expansion reactions yielding higher ring systems or highly substituted acyclic amines. These useful transformations will be described in the second section of this account.