[3 + 2] Cycloaddition reactions of nitrile oxides generated in situ from aldoximes with alkenes and alkynes under ball-milling conditions

ABSTRACT

A convenient and efficient [3 + 2] cycloaddition reaction of alkenes and alkynes with the in situ generated nitrile oxides from aldoximes in the presence of NaCl, Oxone and Na₂CO₃ has been developed to afford a series of isoxazoles and isoxazolines at room temperature in yields up to 85% and 86%, respectively. The current methodology exhibits a wide substrate scope, (hetero)aromatic and aliphatic aldoximes, alkenes including acrylate esters, acrylonitrile, chalcone, styrene, N-methylmaleimide and [60]fullerene, phenylacetylene, and alkynes containing CH₂OH, SiMe₃, COCH₃ or CO₂CH₃ group can be employed. The present protocol features good functional group tolerance, short reaction time, mild reaction conditions and high atom economy, providing an efficient and environmentally friendly access to isoxazoles and isoxazolines.

GRAPHICAL ABSTRACT

KEYWORDS:

• Mechanochemistry
• [3 + 2] cycloaddition
• aldoximes
• nitrile oxides
• alkenes
• alkynes

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The National Natural Science Foundation of China (21372211) and COST (European Cooperation in Science and Technology) Action: CA18112.