Synthesis of 1,4-anhydro-d-fructose and 1,4-anhydro-d-tagatose

1,4-Anhydro-d-fructose and 1,4-anhydro-d-tagatose were prepared from 1,2-O-isopropylidene-d-glucofuranose via the common intermediate 3,5,6-tri-O-benzyl-d-glucitol. The title compounds may be interesting anti-oxidants and feature activities akin to their natural pyranoid counterpart, 1,5-anhydro-d-fructose.