On the preparation of carbohydrate sulfates by displacement of trifluoromethanesulfonates

Abstract

A recent paper by Latif et.al.’ described the reaction of certain carbohydrate trifluoromethanesulfonates (triflates) with tetrabutylammonium hydrogensulfate in acetonitrile solution to produce hydrogensulfates. In a particular example, benzyl 2,3-anhydro-CO-(trifluoromethanesulfonyl)-cr-D-lyxopyranoside (1) was reported to undergo displacement of the triflate group by the hydrogensulfate ion to produce in 59% yield the product benzyl 2,3-anhydro-@=ribopyranoside 4-hydrogensulfate (2, Scheme 1). Compound 2 was reported to be a stable, crystalline solid that could be chromatographed on silica gel with ethyl acetate-hexane elution. ‘Hand ‘3C-n.m.r. spectra in support of structure 2 were provided; mass and infrared spectra were not reported’. In connection with some studies underway in these laboratories, there was a need for a secondary carbohydrate sulfate, and we repeated the process for preparing 2 from 1. From this reaction a compound was obtained whose physical properties (RF, m.p., and ‘Hand “C-n.m.r. spectra) were in excellent accord with those reported’ for 2.