Glycosyl Sulfonates Beyond Triflates

While glycosyl triflates are frequently invoked as intermediates in many chemical glycosylation reactions, the chemistry of other glycosyl sulfonates remains comparatively underexplored. Given the reactivity of sulfonates can span several orders of magnitude, this represents an untapped resource for the development of stereoselective glycosylation reactions. This personal account describes our laboratories efforts to take advantage of this reactivity to develop beta-specific glycosylation reactions. Initial investigations led to the development of 2-deoxy-sugar tosylates as highly selective donors for beta-glycoside synthesis, an approach which has been used to great success by our group and others for the construction of deoxy-sugar oligosaccharides and natural products. Subsequent studies demonstrate that "matching" the reactivity of the sulfonate to that of the sugar donor leads to highly selective S(N)2-glycosylations with a range of substrates.