Preparation of acetylated pyranoid glycals from glycosyl halides by chromium(II) complexes under aqueous biphasic conditions

Reactions of chromium(II) aminocarboxylate complexes (ethylenediamine-tetraacetate, nitrilo-triacetate, imino-diacetate) with acetylated glycopyranosyl chlorides or bromides in liquid–liquid or solid–liquid biphasic media (such as water–diethylether, water–ethyl acetate or halosugar–water) give the corresponding glycals in 75–97% yield.