Preparation of glycosyl halides under neutral conditions
作者:Beat Ernst、Tammo Winkler
DOI:10.1016/s0040-4039(00)99408-5
日期:1989.1
The anomeric hydroxyl group of various furanose and pyranose hemiacetals can be replaced by a fluorine, chlorine, bromine or iodine atom underneutralconditions using haloenamines.
O-(1-Phenyl-1H-tetrazol-5-yl) Glycosides: Alternative synthesis and transformation into glycosyl fluorides
作者:Monica Palme、Andrea Vasella
DOI:10.1002/hlca.19950780418
日期:1995.6.28
A number of new glycosyl donors, O-(1-phenyl-1H-tetrazol-5-yl) glycosides, are prepared from the corresponding hemiacetals, commercially available 5-chloro-1-phenyl-1H-tetrazole (2), and tetrabutylammonium fluoride (Bu4NF) in either THF or DMF. The mild reaction conditions are compatible with a variety of protecting groups. The glycosyl donors are treated with hydrogen fluoride-pyridine complex (HF·py)
由相应的半缩醛,可商购的5-氯-1-苯基-1 H-四唑(2)制备许多新的糖基供体O-(1-苯基-1 H-四唑-5-基)糖苷(2),THF或DMF中的四丁基氟化铵(Bu 4 NF)。温和的反应条件可与多种保护基团相容。糖基供体用氟化氢-吡啶配合物(HF·py)处理,以良好或优异的产率快速提供糖基氟化物,显然是通过(单或双)S N 2机理进行的,正如1 H和19所研究的那样F-NMR光谱。在酸性条件下,糖基氟化物部分或完全平衡,需要大量过量的HF·py进行平衡。
Stereoselective glycosylation of Alcohols and Silyl Ethers Using Glycosyl Fluorides and Boron Trifluoride Etherate
作者:Horst Kunz、Wilfried Sager
DOI:10.1002/hlca.19850680134
日期:1985.2.13
The stereoselective glycosylation of alcohols and their silyl ethers has been achieved using O-alkyl-, O-acyl-, and acetal-protected glycosyl fluorides of the pyranose and furanose series and boron trifluoride etherate in CH2Cl2.
Verfahren zur Herstellung von geschützten Mono- und Oligozuckerhalogeniden
申请人:CIBA-GEIGY AG
公开号:EP0373118A2
公开(公告)日:1990-06-13
Die Umsetzung von geschützten Mono- und Oligosacchariden oder geschützten Mono- und Oligosaccharid-Derivaten, die eine anomere Hydroxylgruppe enthalten, mit sekundären α-Halogenenaminen liefert in hohen Ausbeuten geschützte Glykosylhalogenide, die wertvolle Zwischenprodukte zur Einführung von Zuckergruppen bei der Synthese von Oligosacchariden, Glykolipiden oder Glykopeptiden darstellen.
Deoxyfluorination of alcohols was carried out using N,N-diethyl-alpha,alpha-difluoro-(m-methylbenzyl)amine (DFMBA). Primary alcohols were effectively converted to fluorides under microwave irradiation or conventional heating. Deoxyfluorination of an anomeric hydroxy group in sugars by DFMBA proceeded at below room temperature and glycosyl fluorides could be obtained in good yields. The deoxyfluorination reaction chemoselectively proceeded and various protecting groups on the sugar can survive under the reaction conditions. (C) 2004 Elsevier Ltd. All rights reserved.