Synthetic approach toward antibiotic tunicamycins, 4.₊ x-ray crystal structure analysis of a higher-carbon nitro sugar

A higher-carbon carbohydrate, a derivative of undecose has been synthesized by the potassium fluoride-catalyzed addition of a nitro sugar to a sugar aldehyde. The addition of methyl 5-de-oxy-2,3-0-isopropylidene-5-nitro-6-D-ribofuranoside to methyl 2-benzyloxycarbonylamino-2-deoxy-3,4-0-isopropylidene-a-D-galacto-dialdopyranoside-(1,5) yielded a single diastereomer of the nitro undecose derivative. The absolute configuration of two chiral centers of the derivative has been established by the X-ray crystal structure analysis.