Sugar Nitro-olefins. Part 6. Synthesis of (3R)-3,5,6,7-Tetrahydro-2-hydroxyimino- 3-(penta-O-acetylpentitol-1-yl)benzofuran-4(2H)-ones from 3,4,5,6,7-Penta-O-acetyl-1,2-dideoxy-1-nitrohept-1-enitols and Cyclohexane-1,3-diones.