Branched-chain sugars. Part IV. Synthesis of derivatives of aldgarose, a component of aldgamycin E

Abstract

Methyl 4,6-dideoxy-3-C-[(S)-1-hydroxyethyl]-β-D-ribo-hexopyranoside 3,3¹-cyclic carbonate (methyl aldgaro-side B)(14) has been synthesised and shown to be identical with one of the anomeric glycosides obtained from aldgamycin E by methanolysis. The key step in the synthesis involved the epoxidation of methyl 4,6-dideoxy-2,3-O-isopropylidene-3-C-vinyl-α-D-ribo-hexopyranoside (4) to yield principally the (S)-epoxide (10).