D-Arabinopyranosyl fluoride

In the pentose series, attack has also been observed to occur mainly from the less-hindered side of the double bond, as in the addition of trifluoro(fluoroxy)methane to di-O-acetyl-D-arabinal. Trifluoromethyl 3,4-di-0-acetyl-2-deoxy-2-fluoro-/3-D-arabinopyranoside and 3,4-di-0-acetyl-2-deoxy-2-fluoro-/J-D-arabinopyranosyl fluoride were obtained,72,74 together with a very small proportion of 3,4-di-0-acetyl-2-deoxy-2-fluoro-a-D-ribopyranosyl fluoride.74 With di-O-acetyl-D-xylal, however, the lyxose derivatives were mainly obtained.72,73 The suggestion has been made73 that the greater conformational mobility of pentopyranoses results in a preponderance of the C d) conformer of the D-lyxose derivatives,72,73 such that F-l and CFsO-l are axially disposed. For further reactions of unsaturated carbohydrates with tri-fluoro(fluoroxy)methane, see Section 11,9. 

The LAOCN3 and TWOSUM programs have been used in the iterative analysis or spectrum simulation of tri-O-acetyl-jS-D-arabinopyranosyl fluoride,252 tri-O-benzoyl-a- and /3-D-ribofuranosyl fluoride,253 and 3,6-anhydro-5-deoxy-5-fluoro-l,2-0-isopropylidene-a-L-idofuranose254 (85). 

Di-O-acetyl-a-D-mannopyranosyl bromide 2,3-carbonate, M-41 3,4-Di-0-acetyl-2-0-methyl-p-D-arabinopyranosyl fluoride, A-832... 

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