Preparation of N-nosyl-3,4-epimines derived from levoglucosan by sodium borohydride reduction

Starting from 1,6-anhydro-β-d-glucopyranose 1 (levoglucosan), N-o-nitrobenzenesulfonyl (nosyl) 3,4-epimino derivatives with d-allo, d-galacto, and d-talo configurations have been prepared via NaBH4 reduction of suitably substituted azido tosylates. The benefits and limitations of this method over the classical LiAlH4 reduction method are discussed.