Enantioselective Synthesis of 2-Isoxazolines via Asymmetric 1,3-Dipolar Cycloaddition of Nitrile Oxide to Achiral Allyl Alcohol

The asymmetric 1,3-dipolar cycloaddition of a nitrile oxide to an achiral allyl alcohol was achieved by the use of (R,R)-diisopropyl tartrate as a chiral auxiliary. Treatment of the allyl alcohol with diethylzinc and the tartrate, followed by the addition of diethylzinc and a hydroximoyl chloride, afforded the corresponding (R)-2-isoxazolines with excellent enantioselectivity.