The nitrile oxide-isoxazoline approach to 11-carbon monosaccharides. Conversion of 3-(tetritol-1-yl)-5-(tetrofuranos-4-yl)-2-isoxazolines into 6-deoxyundecoses

Hydrogenolysis of (5R)-3-(1,2:3,4-di-O-isopropylidene-D-arabino-tetritol-1- yl)-5-(3-O-benzyl-1,2-O-isopropylidene-alpha-D-xylo-tetrofuranos-4-yl)-4,5- dihydroisoxazole afforded the 7-ulose derivative, from which 6-deoxy-D-gluc o-D-gluco- and D-manno-D-gluco-undecose derivatives 17 and 18 were prepared by reduction with sodium borohydride or L-Selectride. The configuration of the new stereogenic centre (C-7) in compounds 17 and 18 was established by NMR analysis of their 5,7-O-isopropylidene derivatives. 6-Deoxy-L-manno-D- gluco- and L-gluco-D-gluco-undecose analogues 19 and 20 were prepared simil arly from the isomeric 3-(L-arabino-tetritolyl)-4,5-dihydroisoxazole. Remov al of the isopropylidene protecting groups from compounds 17 and 20 yielded 3-O-benzyl-6-deoxy-D-gluco- and L-manno-D-gluco-undecopyranoses, which wer e characterised as their octa-acetate derivatives. The corresponding reacti on sequence from 3-(D- and L-arabino-tetritol-1-yl)-5-(2,3-O-isopropylidene -3-O-methyl-alpha-D-lyxo-tetrofuranos-4-yl)-4,5-dihydroisoxazoles afforded 6-deoxy-D/L-gluco-D-manno and D/L-manno-D-manno-undecose derivatives. (C) 1 999 Elsevier Science Ltd. All rights reserved.