Synthesis of l-gulose, l-galactose, and their acetylated aldehydo forms from 6-S-phenyl-6-thio-d-hexoses

Conversion of Alcohols to Phosphorothiolates Using a Thioiminium Salt as Coupling Agent

“…1,2:3,4-Di- O -isopropylidene- d -galactopyranose 4n proved unreactive under the reaction conditions and was recovered unchanged. The low reactivity of leaving groups at the 6-position of galactopyranose derivatives has been noted previously, although it should be noted that 4n has been shown to react with several sulfur nucleophiles under Mitsunobu conditions or with PhSSPh/Bu 3 P . In the present case, slow formation of EtSPO­(OEt) 2 ( 9 ) was observed, presumably from direct reaction of thioiminium salt 2 with phosphorothiolate anion 7 .…”

Synthesis of l-Hexoses

“…Head-to-tail inversion has also been completed taking advantage of a Pummerer rearrangement . Installation of a thioether at C6 can be carried out by reaction of the 6-OH with diphenyl disulfide in the presence of tributylphosphine.…”

“…Head-to-tail inversion has also been completed taking advantage of a Pummerer rearrangement. 210 Installation of a thioether at C6 can be carried out by reaction of the 6-OH with diphenyl disulfide in the presence of tributylphosphine. Reduction of the 6-deoxy-6-thiophenyl D-glucose 183 followed by peracetylation gave thioether 184, which could be oxidized to the sulfoxide 185 (Scheme 28).…”

Synthesis of L‐Hexoses: An Update

“…[21] Their strategy circumvents the disadvantages of existing lengthy routes and low yielding reaction strategies for the preparation of Lgulose. [22][23][24]29] Accordingly, acetonide protection in D-glucuronolactone 1 is carried out using conc. H 2 SO 4 and acetone, followed by protection of the remaining free hydroxyl group using BnBr to afford protected compound 2.…”