SYNTHESES OF 6-DEOXYHEX-5-ENOPYRANOSIDES FROM 6-BROMO-6-DEOXYHEX OR 6-O-P-TOLYLSULFONYLHEXOPYRANOSIDES BY THE USE OF DBU IN DMSO

Various kinds of nonbranched and methyl-branched 6-deoxyhex-5-enopyran oside derivatives were prepared from 6-bromo-6-deoxy or 6-O-p-tolylsul fonylhexopyranoside in a one-pot procedure by a successive treatment w ith iodide anion and 1,8-diazabicyclo[5.4.0]undec-7-ene in dimethyl su lfoxide. The scope and limitations of this reaction have become appare nt by observing the reactions of 18 substrates. The yields of altropyr anoside and 2-deoxyribo-hexopyranoside derivatives were high, except f or the 2,3-anhydropyranoside derivative. Methyl-branched 6-deoxyhex-5- enopyranoside derivatives were also obtained in practical yields.