Chemical modification of trehalose. Part XI. 6,6′-Dideoxy-6,6′-di-fluoro-αα-trehalose and its galacto-analogue

Abstract

2,2′,3,3′,-Tetra-O-benzyl-αα-trehalose (3) was converted into both the 4,4′,6,6′-tetramesylate (4) and the 6,6′-di-tosylate (5), which underwent displacement of their primary sulphonyloxy-groups by fluoride when treated with tetra-n-butylammonium fluoride in an aprotic dipolar solvent, to give the corresponding 6,6′-difluoro-derivatives. Removal of the protecting'groups afforded 6,6′-dideoxy-6,6′-difluoro-αα-trehalose (8).

The 6,6′-difluoro-4,4′-dimesylate (6) derived from the tetramesylate (4) underwent nucleophilic displacement of the 4,4′-disulphonyloxy-groups with benzoate anion to give, after removal of the blocking groups, 6,6′-dideoxy-6,6′-difluoro-αα-galacto-trehalose (13).