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Published on: August 16, 2018
Nucleophilic substitution reactions of pyranose polytosylates
Ross P McGeary1, Sara Rasoul Amini, Vincent W S Tang
1Chemistry Department, School of Molecular and Microbial Sciences, and School of Pharmacy, The University of Queensland, Brisbane, Qld 4072, Australia. r.mcgeary@mailbox.uq.edu.au
Abstract:
The 2,3,4-tri-toluenesulfonate ester derivatives of the methyl pyranosides of l-arabinose, d-ribose, d-lyxose, and d-xylose have been prepared, and their substitution reactions with various nucleophiles have been examined. For arabinose, xylose, and ribose, highly regioselective monosubstitutions were observed with benzoate, nitrite, and azide anions. These reactions have led to short and simple routes from d-xylose to l-arabinose derivatives, from l-arabinose to d-xylose derivatives, and from d-ribose to l-lyxose derivatives. The tritosylate derived from methyl alpha-d-lyxopyranoside was unreactive toward nucleophilic substitution reactions, giving instead a dihydropyran product arising from an initial E2 elimination reaction of the 2-tosylate.
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