Utilisation d'ylides du phosphore en chimie des sucres. XI. Synthèse des quatre didésoxy-3, 5-méthyl-3-pentoses parl'intermédiaire de sucres insaturés ramifiés
✍ Scribed by J. M. J. Tronchet; R. Graf
- Publisher
- John Wiley and Sons
- Year
- 1972
- Tongue
- German
- Weight
- 712 KB
- Volume
- 55
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Treated with methylthiomethylenetriphenylphosphorane, 5‐deoxy‐1,2‐O‐iso‐propylidene‐β‐D‐threo‐ and ‐α‐D‐erythro‐furanos‐3‐uloses led with good yields to a mixture of the cis‐trans isomers of the corresponding methylthiovinylidenic sugars. There was no inversion of configuration at C(4) with the thero‐furanosulose and a small one (7%) with its erythro isomer. These unsaturated branched‐chain thio‐sugars are useful synthetic intermediates. For examples, the desulfurization‐hydrogenation (Raney Nickel) of each of these alkenes afforded in good yield two 3‐deoxy‐3‐C‐methyl‐pentoses epimeric at C(3) and having the same configuration at C(4) as the starting alkenes. In all cases the isomer formed by attack from the less hindered face of the double bond was the preponderant one.
📜 SIMILAR VOLUMES
## 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
## 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
## Abstract The synthesis of branched‐chain sugars of the __gem__‐hydroxy‐formyl and the __gem__‐hydroxy‐hydroxymethyl types is described. A 5‐deoxy‐1,2‐O‐isopropylidene‐furanos‐3‐ulose is treated with cyanomethylene‐triphenyl‐phosphorane, yielding the two geometrical isomers of the corresponding b
## Abstract The treatment of the 1, 2:5, 6‐di‐O‐isopropylidene‐α‐D‐__ribo__‐ and __xylo__‐hexofuranos‐3‐uloses with cyanomethylenetriphenylphosphorane led in each case, and in almost quantitative yields, to a pair of geometrical isomers of C‐cyanomethylenic sugars having respectively the __ribo__ a
## Abstract The __cis__ and __trans__ isomers of 3‐deoxy‐1,2:5,6‐di‐O‐isopropylidene‐3‐C‐methylthiomethylene‐α‐D‐__xylo__‐ and ‐α‐D‐__ribo__‐hexofuranoses have been prepared by treatment of 1,2:5,6‐di‐O‐isopropylidene‐α‐D‐__xylo__‐ and ‐α‐D‐__ribo__‐hexofuran‐3‐uloses with methylthiomethylene‐triph