Stereospecific synthesis of methyl D,L-hex-2-ulopyranosides from furan compounds

2-Benzyloxymethyl-5-hydroxymethylfuran was converted, according to the known method, into methyl 1-O-benzyl-3,4-dideoxy-d,l-hex-3-en-2-ulopyranos-5-ulose. Reduction of the latter and hydroxylation or epoxidation, followed by the oxirane ring opening, afforded the title compounds with α-sorbo-, β-fructo-, α-tagato- and α-pisco- configuration. The steric course of reduction, hydroxylation and epoxidation reactions were examined.