Glucal hydrogen fluoride

Tri-( -benzoyl-D-glucal is hydrofluorinated with hydrogen fluoride at — 70 C for 20 hours to yield 3,6-di-0-benzoyl-2-deoxy-a-D-n7)o-hexopyranosyl fluoride (5). ... 

A method using silver(I) fluoride and chlorine is sufficiently mild for the isolation of the chlorine fluoride adducts in good yield, whereas the combination of IV-chlorosuccinimide and hydrogen fluoride gives no fluorinated products. The reaction of chlorine with a suspension of D-glucal triacetate and silver(I) fluoride in an acetonitrile/benzene solution is unusual in that it gives all four possible 3,4,6-tri-0-acetyl-2-chloro-2-deoxy-D-glycopyranosyl fluorides... 

The addition of the elements of IF with silver fluoride/iodine toD-glucal triacetate - leads to similar results to the corresponding bromofluorination (Section 1.2.1.3.2.). The three products are 3,4,6-tri-0-acetyl-2-deoxy-2-iodo-a-D-mannopyranosyl fluoride (5, 60 Vo), 3,4.6-tri-0-acetyl-2-deoxy-2-iodo-/l-D-glucopyranosyl fluoride (6, 34%), and 3,4,6-tri-0-acctyl-2-deoxy-2-iodo-a-D-glucopyranosyl fluoride (7,6 %). lodofluorination with hydrogen fluoride/At-iodosuccinimide gives the same three fluorides 5/6/7 in 71, 3 and 23 Vo yield. 

I. Lundt and C. Pedersen, Reaction of tri-O-acetyl- and tri-O-benzoyl-D-glucal with hydrogen fluoride, Acta Chem. Scand, 20 (1966) 1369-1375. 

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