METAL-HYDRIDE REDUCTION OF ISOXAZOLINE-3-CARBOXYLATE ESTERS

The reduction of a series of isoxazolino-3-carboxylate esters with sodium borohydride gave 3-(hydroxymethyl)isoxazolines in 34-98% yield. Reduction with DIBAH gave isoxazoline-3-carboxaldehydes in 63 and 85% yields for the two reactions studied. Isoxazoline-3-carboxaldehydes could also be prepared by Swern oxidation of the corresponding 3-(hydroxymethyl)isoxazolines. The hydroxyl group of 3-(hydroxymethyl)isoxazoline 11b was silylated and the endocyclic double bond was cleaved by ozonolysis to produce a monosilylated triol