Osmium Catalyzed Dihydroxylation of 1,2-Dioxines: A New Entry for Stereoselective Sugar Synthesis

A series of 3,6-substituted 3,6-dihydro-1,2-dioxines were dihydroxylated with osmium tetroxide to furnish
1,2-dioxane-4,5-diols (peroxy diols) in yields ranging from 33% to 98% and with de values not less than
90%. The peroxy diols were then reduced to generate a stereospecific tetraol core with R,R,S,S or “allitol”
stereochemistry. The peroxy diols and their acetonide derivatives were also ring-opened with Co(II)
salen complexes to give novel hydroxy ketones in 77−100% yield, including the natural sugar psicose.
Importantly, preliminary work on the catalytic asymmetric ring-opening of meso-peroxy diols using the
Co(II) Jacobsens's catalyst indicates that asymmetric sugar synthesis from 1,2-dioxines is possible.