Mechanochemical Desymmetrization of Unbiased Bis‐ and Tris‐alkynes to Access 3,5‐Isoxazoles‐Alkyne Adducts and Unsymmetrical Bis‐3,5‐isoxazoles**

Abstract

AbstractA mechanochemical desymmetrization of symmetrical bis‐ and tris‐alkynes by a controlled 1,3‐dipolar cycloaddition reaction using nitrile oxide dipoles (NOs). This operationally simple protocol allows access to 3,5‐isoxazole‐alkyne adducts from easily prepared or commercially available symmetrical bis‐ and tris‐alkynes in moderate to excellent yields. In addition, we have highlighted the synthetic utility of 3,5‐isoxazole‐alkyne by developing a route to access, for the first time, β‐ketoenamine‐alkyne derivatives, and unsymmetrical bis‐3,5‐isoxazoles.