Regio- and stereo-selective synthesis of carbohydrate isoxazolidines by 1,3-dipolar cycloaddition of nitrones to 5,6-di-deoxy-1,2- O -isopropylidene-α- d - xylo -hex-5-enofuranose
The synthesis of 2-phenyl-3-aryl and 2-phenyl-3-aroyl derivatives 5-(1,2-O-isopropylidene-alpha-D-xylo-tetrofuranos-4-yl)isoxazolidi ne (3) from nitrones and 5,6-dideoxy-1,2-O-isopropylidene-alpha-D-xylo-hex-5- enofuranose (1) is described. The 1,3-dipolar cycloaddition reactions given mainly anti adducts 3 and 4 (greater than or equal to 95% pi-facial stereoselectivity). The cycloadducts 3 with H-3