Recent Advances in the Synthesis of Isoxazolidines

An isoxazolidine is a pentatomic heterocycle, containing adjacent nitrogen and oxygen atoms. This ring is present in many compounds, showing significant biological activity, and plays a very significant role in the preparation of nucleotide and nucleoside analogs, which are used as anticancer and antiviral agents in medicinal chemistry. This chapter summarizes the last five years of the literature on the synthesis of isoxazolidines using conventional and modern methods, with reference to the structures of the products (i.e. substituted isoxazolidines, fused isoxazolidines, spiro-isoxazolidines, nucleoside and nucleotide analogs) obtained by cycloaddition reactions. Organocatalysts have been much used in the synthesis of substituted isoxazolidines in recent years. In particular, the employment of chiral metal complexes plays an important role in improving the reactivity and providing better control of the selectivity of cycloaddition reactions. The fused isoxazolidine presents a second ring fused to the isoxazolidine moiety, making the structure rigid and conformationally restricted.