3- Deoxy-3-fluoro-D-mannitol

Deoxy-4-fluoro-D-fructose (552) was prepared (59%) by fermentation of 3-deoxy-3-fluoro-D-mannitol with Gluconobacter oxydans. The structure of 552 (fi-T) form) was confirmed by the n.m.r. spectrum, which resembles that of 4-deoxy-4-fluoro-Q -D-sorbopyranose (553) 552 was identical with one of the products obtained from the oxirane-ring opening of 3,4-anhy-dro-l,2-0-isopropylidene- -D-tagatopyranose with KHFj. 

Enzymatic dehydrogenation of 3-deoxy-3-fluoro-D-mannitol using enzymes of Gluconobacter oxydana provides a route to i4,-deox -4.-fluoro-D-fructose, whose structure was confirmed b H, C, and F n.m.r. spectroscopy. The molecule adopts the C (D) conformation in aqueous solution. 

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