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Glucal

About: Glucal is a research topic. Over the lifetime, 590 publications have been published within this topic receiving 8960 citations. The topic is also known as: D-glucal.


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Journal ArticleDOI
TL;DR: In this article, the reaction of 3,4,6-tri-O-acetyl-1,2-dideoxyhex-1-enopyranoses (glycals) in dimethyl phosphite catalysed by boron trifluoride affords dimethyl (4, 6-di-O,acetyl)-2,3-didcoxyhex-2,enopeyranosylphosphonates by allylic rearrangement.
Abstract: 3,4,6-Tri-O-acetyl-1,2-didesoxyhex-1-enopyranosen (Glycale) reagieren in Dimethylphosphit bei BF3-Katalyse unter Allylumlagerung zu Dimethyl-(4,6-di-O-acetyl-2,3-didesoxyhex-2-enopyranosyl)phosphonaten. In der Pentose-Reihe verlauft die Reaktion entsprechend. Hei Einsatz der arabino-Verbindung 2 (Glucal) und der ribo-Verbindung 5 (Allal) wird das gleiche Anomeren-Verhaltnis 3a zu 6a (1 : 2) erhalten. Bei Reaktion der lyxo-Verbindung 8 (Galactal) und der xylo-Verbindung 11 (Gulal) enthalt das gemeinsame Produkt α-Form 9a und β-Form 12a im gleichen Verhaltnis (1 :3). Die Befunde sprechen fur eine SN1-Reaktion mit Umlagerung. Die Phosphonsaure-dialkylester lassen sich durch Umesterung zu Bistri-methylsilylestern unter milden Bedingungen in freie Phosphonsauren uberfuhren. 1H-NMR-, 31P-NMR-und Massenspektren der 2-Enopyranosylphosphonate werden diskutiert. Die Hex-2-enopyranosylphosphonate bevorzugen die OH5(D)-Halbsesselkonformation 37. Phosphorus-containing Carbohydrates, VIII. Synthesis of Glycopyranosylphosphonates by Addition of Dialkyl Phosphites to Glycals with Allylic Shift The reaction of 3,4,6-tri-O-acetyl-1,2-dideoxyhex-1-enopyranoses (glycals) in dimethyl phosphite catalysed by boron trifluoride affords dimethyl (4,6-di-O-acetyl-2,3-didcoxyhex-2-enopyranosyl)phosphonates by allylic rearrangement. A corresponding reaction proceeds in the pentose series. On treatment of the arabino-compound 2 (glucal) or the ribo-compound 5 (allal) the same anomeric distribution 3a to 6a (1 :2) is obtained. In the corresponding reaction or the lyxo-compound 8 (galactal) or the xylo-compound 11 (gulal) the mutual product contains α-form 9a and β-form 12a again in the same ratio (1:3). These findings support a SNl reaction with rearrangement. Via transesterification of the dialkyl esters to bistrimethyl-silyl phosphonates the free phosphonic acids are obtained under very mild conditions. 1H n.m.r., 31P n.m.r., and mass spectra of the 2-enopyranosylphosphonates are discussed. The hex-2-enopyranosylphosphonates prefer the OH5(D) half chair conformation 37.

39 citations

Journal ArticleDOI
TL;DR: The findings allow the azidonitration reaction to be now used for the preparation of a variety of glucosamine building blocks from differentially protected glucal precursors.

38 citations

Journal ArticleDOI
TL;DR: In this paper, polymer-supported electrophilic reagents are prepared which efficiently add to carbohydrate-derived glycals under very mild conditions, and 2-deoxy-2-halo-pyranosyl acetates or azides are generated in excellent yield.

38 citations

Journal ArticleDOI
TL;DR: 6-O-Trityl- and 6-(O-benzyl)-substituted epoxide derived from D-glucal were examined in their addition reactions with O, C, N, and S-nucleophiles and a 1,2-syn-addition pathway was observed.
Abstract: 6-O-Trityl- (1a) and 6-(O-benzyl)-substituted epoxide (1b) derived from d-glucal were examined in their addition reactions with O-, C-, N-, and S-nucleophiles. A 1,4-regio- and β-stereoselective or an anti 1,2-addition pathway is commonly observed depending on the ability of the nucleophile to coordinate with the oxirane oxygen. When TMSN3 or LiN3 are used as azide-based nucleophiles, a 1,2-syn-addition pathway is also observed.

37 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20233
20224
20212
20204
20193
20186