Investigation of the base promoted tandem syn-elimination–Favorskii rearrangement of levoglucosan sulfonates
Abstract
The reaction of various 2,3,4-trisulfonated 1,6-anhydro-β-D-glucopyranoses with alkoxide was investigated. Upon treatment with methoxide the tritosylate5, tris(chlorosulfate) 20 and tris(trifluoromethanesulfonate) 21 all gave 1,5-anhydro-2,3-dideoxy-3-methoxycarbonyl-β-D-erythro-pentofuranose 6 in 41–57% yield with the yield increasing with improved leaving group ability. The trimesylate19 gave the 3,4-epoxide 23 and no rearranged product.