Displacement reactions of acyclic carbohydrate derivatives. Part III. Aldehyde group participation in 2,3,5-tri-O-benzyl-4-O-toluene-p-sulphonyl-aldehydo-D-ribose

Abstract

Acidic hydrolysis of 2,3,5-tri-O-benzyl-4-O-toluene-p-sulphonyl-D-ribose dimethyl acetal gave 2,3,5-tri-O-benzyl-4-O-toluene-p-sulphonyl-aldehydo-D-ribose which was readily hydrolysed further to 2,3,5-tri-O-benzyl-L-lyxofuranose. Treatment of the aldehydo-compound with sodium methoxide in methanol gave methyl 2,3,5-tri-O-benzyl-L-lyxofuranoside. These easy displacements of the sulphonate group are rationalised in terms of neighbouring-group participation by the aldehyde group.