Utilisation d'ylides du phosphore en chimie des sucres. XX. Synthèse de sucres acétyléniques et réarrangment d'intermédiaires carbénoïdes. Communication préliminaire
✍ Scribed by Jean M. J. Tronchet; Alberto Gonzalez; Jean-Bernard Zumwald; Françoise Perret
- Publisher
- John Wiley and Sons
- Year
- 1974
- Tongue
- German
- Weight
- 360 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0018-019X
No coin nor oath required. For personal study only.
✦ Synopsis
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. The second method involves an one‐step reaction between an aldehydo‐sugar and dimethyl diazomethylphosphonate. The acetylenic sugars obtained are valuable synthetic intermediates for the preparation of heterocyclic C‐nucleosides by 1,3‐dipolar cycloaddition reactions and some examples of syntheses of this type are described. Treatment of keto‐sugars with dimethyl diazomethylphosphonate led to an intermediate carbenoid species which reacted by insertion into a CH bond in one case and underwent nucleophilic attack by a methoxy group in a second case.
📜 SIMILAR VOLUMES
## Abstract Several sugars with conjugated unsaturation (dienes or α, β‐unsaturated carbonyl compounds) have been synthesised by use of __Wittig__ reactions. Keto‐sugars bearing a carbonyl group α to a furanose ring are prone to undergo an elimination leading to conjugated unsaturated systems. This
## Abstract The previously described one‐carbon chain extension of __aldehydo__‐sugars with methylthiomethylene‐triphenylphosphorane has been successfully applied to an anhydro‐__aldehydo__‐sugar and two __w__‐__aldehydo__‐sugars. Some spectroscopic properties of the so obtained methylthiovinylic s
## Abstract __Cis__ and __trans__‐methyl‐4‐deoxy‐2, 3‐O‐isopropylidene‐6‐O‐methyl‐4‐methylthio‐methylene‐α‐D‐__lyxo__‐hexopyra‐nosides are prepared by a __Wittig__ reaction. Methods are described for the determination of the configuration of the geometrical isomers whose __Raney__‐Nickel reduction