Peracetylated 1,6-dibromo-D-glucitol as efficient precursor of 1,6-diiodo and some mono-, disubstituted and heterocyclic D-glucitol derivatives.

2,3,4,5-Tetra-O-acetyl-1,6-dibromo-1,6-dideoxy-D-glucitol (1a) obtained from D-glucitol was easily transformed into the 1,6-diiodo derivative in excellent yield (97%) by reaction with an excess of sodium iodide in refluxing butanone in 2 h. When the reaction time was prolonged to 24 h and the crude product was acetylated, 1,2,3,4,5-penta-O-acetyl-6-deoxy-6-iodo-D-glucitol and D-glucitol hexaacetate were isolated in 50 and 26% yields, respectively. The monodehalogenation then took place regioselectively at C-1. This regioselectivity allowed the synthesis of some mono- and disubstituted derivatives of D-glucitol. Thus, the peracetylated derivatives of D-glucitol, 6-bromo, 6-bromo-1-S-butyl, 6-bromo-1-S-octyl, 6-S-butyl, 6-S-butyl-1-S-octyl, 1-S-butyl, 1,6-di-S-octyl and 6-S-phenyl were synthesised in good to excellent yields. With S= as binucleophilic reagent, 1a gave mainly the thiepane derivative (75%) plus the 1-S-acetyl-2,6-anhydro-D-glucitol derivative as a by-product (10%).