Syntheses of 6-Deoxyhex-5-enopyranosides from 6-Bromo-6-deoxy- or 6-O-p-Tolylsulfonylhexopyranosides by the Use of DBU in DMSO

Abstract
Various kinds of nonbranched and methyl-branched 6-deoxyhex-5-enopyranoside derivatives were prepared from 6-bromo-6-deoxy or 6-O-p-tolylsulfonylhexopyranoside in a one-pot procedure by a successive treatment with iodide anion and 1,8-diazabicyclo[5.4.0]undec-7-ene in dimethyl sulfoxide. The scope and limitations of this reaction have become apparent by observing the reactions of 18 substrates. The yields of altropyranoside and 2-deoxyribo-hexopyranoside derivatives were high, except for the 2,3-anhydropyranoside derivative. Methyl-branched 6-deoxyhex-5-enopyranoside derivatives were also obtained in practical yields.