Convenient synthesis of multi-substituted isoxazoles including a sulfonamide skeleton based on <i>N</i>-sulfonylketenimine and hydroxyimidoyl chloride

The synthesis of functionalized isoxazole including a sulfonamide skeleton with appropriate yields through a novel three-component reaction from sulfonyl azides, terminal alkynes, and various hydroxyimidoyl chlorides is a remarkable achievement in heterocycle chemistry. This strategy offers a direct and efficient route to access different isoxazoles with a sulfonamide substitution from readily available starting materials. The use of copper (I) as a catalyst, without adding ligand, in THF solvent, and with the help of ultrasonic conditions for 30 minutes at room temperature highlights the importance of transition metal catalysis in this process. The combination of available starting materials, catalytic systems, mild reaction conditions, and ease of purification procedures contributes to the attractiveness of this method for the synthesis of diverse new substituted isoxazoles including a sulfonamide skeleton.