Transformation of D-Xylose to (1R,2R,3R,4R)-2,3,4-Trihydroxy-1-(hydroxymethyl)cyclopentane, Pseudo-β-D-arabinofuranose

Article abstract of DOI:10.1246/bcsj.60.3673

The known 3-O-benzyl-D-xylose was converted into methyl (4S,5R,6R)-4,6,7-triacetoxy-5-benzyloxy-2-(methoxycarbonyl)heptanoate (8) by employing Knoevenagel condensation of 2,4,5-tri-O-acetyl-3-O-benzylaldehydo-D-xylose with dimethyl malonate as a key reaction.O-Deacetylation of 8 and successive glycol cleavage followed by acetylation gave a mixture of (1S,4R,5R,6R)-5-acetoxy-6-benzyloxy-4-methoxycarbonyl-2-oxobicyclo<2.2.1>heptan-3-one and dimethyl (2R,3R,4S)-2,4-diacetoxy-3-benzyloxy-1,1-cyclopentanedicarboxylate (12), which was converted into 12 exclusively.This enentiomerically pure highly oxyganated cyclopentane dicarboxylate 12 was converted into (3S,4S)-3-benzyloxy-1-(t-butyldiphenylsilyloxymethyl)-4-hydroxy-1-cyclopentene (15) by 1) thermal demethoxycarbonylation accompanied by β-elimination of the acetoxyl group, 2) diisobutylaluminium hydride reduction, and 3) selective protection of thus formed 1-cyclopentene-1-methanol.Pyridinium chlorochromate oxidation of 15 followed by reduction with sodium borohydride gave a 6.4:1 mixture of (3S,4R)-3-benzyloxy-1-(t-butyldiphenylsilyloxymethyl)-4-hydroxy-1-cyclopentene (18) and 15.Hydroboration of O-desilyl derivative of 18 proceeded stereoselectively from the less hindered α-face, and (1R,2R,3R,4R)-2,4-diacetoxy-1-acetoxymethyl-3-(benzyloxy)cyclopentane (21) was obtained after acetylation.Deprotection of 21 gave pseudo-β-D-arabinofuranose.