Synthesis of 2,3,4-Trideoxy-2,3,4-trifluoroglucose

There
is an increasing interest in investigating how polyfluorination
of carbohydrates modifies their physical and biological properties.
An example that has caught much attention is 2,3,4-trideoxy-2,3,4-trifluoroglucose.
Four syntheses of this compound have been reported, which are either
low yielding or long (13 or more steps). We report a 6-step synthesis
of 2,3,4-trideoxy-2,3,4-trifluoroglucose starting from levoglucosan.
The solution-phase structure of an intermediate, 1,6-anhydro-2,4-dideoxy-2,4-difluoroallose,
features a rare example of a bifurcated F···H­(O)···F
hydrogen bond and is compared to its crystal structure.

当下，学界对探究糖类多氟取代如何改变其物理与生物学特性的兴趣与日俱增。其中备受关注的一例为2,3,4-三脱氧-2,3,4-三氟葡萄糖。目前已有该化合物的四条合成路线被报道，但均存在产率偏低或合成步骤冗长（需13步及以上）的问题。本文报道了一条以左旋葡聚糖（levoglucosan）为起始原料、仅需6步的2,3,4-三脱氧-2,3,4-三氟葡萄糖合成路线。该反应的中间体1,6-脱水-2,4-二脱氧-2,4-二氟阿洛糖的溶液相结构，展现出一例罕见的分叉型F···H(O)···F氢键，研究人员将其与该中间体的晶体结构进行了对比分析。