[2 + 2 + 1] Cycloaddition of -tosylhydrazones, -butyl nitrite and alkenes: a general and practical access to isoxazolines.

-Tosylhydrazones have proven to be versatile synthons over the past several decades. However, to our knowledge, the construction of isoxazolines based on -tosylhydrazones has not been examined. Herein, we report the first demonstrations of [2 + 2 + 1] cycloaddition reactions that allow the facile synthesis of isoxazolines, employing -tosylhydrazones, -butyl nitrite (TBN) and alkenes as reactants.

Acyclic nitronate olefin cycloaddition (ANOC): regio- and stereospecific synthesis of isoxazolines.

We report the first demonstrations of intra- and intermolecular acyclic nitronate olefin cycloaddition (ANOC) reactions that enable the highly efficient syntheses of isoxazolines bearing various functional groups. This general approach to accessing γ-lactone fused isoxazolines was hitherto unprecedented. The room temperature transformations reported herein exhibit wide substrate scopes, as evidenced by more than 70 examples, including the generation of five tricyclic isoxazolines.