✍ Scribed by Jean M. J. Tronchet; Alain P. Bonenfant; Françoise Perret; Alberto Gonzalez; Jean-Bernard Zumwald; Ernesto M. Martinez; Bruno Baehler
No coin nor oath required. For personal study only.
Synthesis of Terminal Acetylenic Sugars Derivatives and Ynuronic Acids Derivatives by Use of a Wittig Reaction
The method described for the preparation of terminal acetylenic sugars presents two advantages over earlier procedures: no new asymmetric center is created and the chain can be extended by one or more C‐atoms. The method also allows preparation of ynuronic acids. The aldehydosugars derivatives 1–7 gave in good to excellent yields the corresponding gem‐dibromoenoses 8–14 from which either the terminal acetylenic sugars derivatives 15–21 or the ynuronic acids 22–24 were easily prepared. A few examples of 1,3‐dipolar cycloadditions (leading to 28–30) with these acetylenic sugar derivatives are also described.
📜 SIMILAR VOLUMES
## Abstract The syntheses of three types of sugar nitrones (aldonitrone, ketonitrone and α‐β unsaturated aldonitrone) are described. On 1,3‐dipolar cycloaddition with phenylacetylene, the aldonitrone gave two Δ~4~‐isoxazolines epimeric at the new asymetric carbon, while the same reaction on the ket
**Use of the __Wittig__ reaction for the synthesis of derivatives of bromoenosuloses and bromoenuronic esters** Treatment of 3‐__O__‐benzyl (or 3‐__O__‐methyl)‐1, 2‐__O__‐isopropylidene‐α‐D‐__xylo__‐pentodialdo‐1, 4‐furanoses (**2** or **1**) with acetylbromomethylidenetriphenylphosphorane (**3**),
**Regioselective Oxidations, Regioselective Halogenations and Carbene Reactions of Sugar Derivatives Bearing a Thioether Group** Regioselective stoechiometrically controlled procedures are described for the oxidation of thiosugars either at the sulfur atom (to sulfoxides or sulfones) or at a hydrox
## Abstract Two novel methods for the synthesis of terminal acetylenic sugars, both involving a chain extension by one carbon unit, are described. In the first procedure, an aldehydo‐sugar is treated with dibromomethylenetriphenyl‐phosphorane, then with __n__‐butyllithium and finally with water. Th
## Prkparation de composks acktylkniques deut6riCs IV -Obtention d'aldkhydes a -acktylkniques deutkriks sur la fonction aldkhyde R e y le 14 avril 1970.