Synthesis of a Novel Spiro-Oxadiazolidines by the Reaction of 1,3-Dipolar Cycloaddition of Nitrile Oxides to 2-Iminothiazolidines

Nitrile oxides are known in various reactions of 1,3-dipolar cycloaddition, where examples of the interaction of this dipole along exocyclic multiple carbon–carbon and carbon–heteroatom bonds are of particular interest. Such substrates can be used to create spiro-conjugated heterocyclic systems with high conformational rigidity, allowing achieving the required stereoelectronic properties in the resulting molecules. Herein, we propose a novel approach to the synthesis of spiro-oxadiazolidines by the reaction of nitrile oxides with 2-iminothiazolidines, which proceeds without isomerization of the starting heterocycles.