Reaction of 1,2-trans-glycosyl acetates with phosphorus pentachloride: new efficient approach to 1,2-trans-glycosyl chlorides
作者:Farid M Ibatullin、Stanislav I Selivanov
DOI:10.1016/s0040-4039(02)02446-2
日期:2002.12
Reaction of phosphoruspentachloride with 1,2-trans-glycosyl esters is described. The reactionmechanism presumably involves formation of a tetrachlorophosphonium ion as one of the key reactive intermediates, which can be induced either by Lewis acids or by using acetonitrile as the reaction solvent. Two novel, efficient methods for the synthesis of the thermodynamically unstable glycosyl chlorides
This report describes an efficient chemoenzymatic synthesis of a variety of regioselectively modified β(1→4)-oligo- and -polysaccharides. This successful approach was based on: (i) the use of a “glycosynthase” which is a Glu-197-Ala nucleophile mutant of the retaining cellulase endoglucanase I (Cel7B) from Humicola insolens and (ii) the rational design of modified acceptor and donor molecules through
本报告描述了多种区域选择性修饰的 β(1→4)-寡糖和多糖的有效化学酶法合成。这种成功的方法基于:(i) 使用“糖合酶”,它是来自 Humicola insolens 的保留纤维素酶内切葡聚糖酶 I (Cel7B) 的 Glu-197-Ala 亲核突变体和 (ii) 修饰受体的合理设计和通过仔细检查野生型酶和突变酶的 X 射线结构给出的信息来确定供体分子。该突变体能够以高产率催化未取代和被各种单糖和二糖受体修饰的 α-糖二糖基氟的区域和立体选择性糖基化,以及通过单步反转机制聚合这些供体。
Stereoselective Preparation of
<i>C</i>
‐Aryl Glycosides
<i>via</i>
Visible‐Light‐Induced Nickel‐Catalyzed Reductive Cross‐Coupling of Glycosyl Chlorides and Aryl Bromides
作者:Ze‐Dong Mou、Jia‐Xi Wang、Xia Zhang、Dawen Niu
DOI:10.1002/adsc.202100343
日期:2021.6.21
A nickel-catalyzed cross-coupling reaction of glycosyl chlorides with aryl bromides has been developed. The reaction proceeds smoothly under visible-light irradiation and features the use of bench-stable glycosyl chlorides, allowing the highly stereoselective synthesis of C-aryl glycosides.
Darstellung und Konformation der 1,2-cis-Pentopyranosylazide
作者:Zoltán Györgydeák、László Szilágyi
DOI:10.1002/jlac.198619860810
日期:1986.8.15
Die Umsetzung der acetylierten 1,2-trans-Pentopyranosylhalogenide 1a, b, 2, 3 mit NaN3 in HMPT unter milden Bedingungen ergibt die 4 möglichen 1,2-cis-2,3,4-Tri-O-acetylpentopyranosylazide 4, 6, 8 und 14, die durch Entacetylierung in die freien Azide 5, 7, 9 und 15 übergeführt werden. Anhand der vicinalen Proton-Proton-Kopplungskonstanten werden die 4C1(D)⇌1C4(D)-Konformationsgleichgewichte in Lösung
Reaction of some 1,2-trans-aldose peracetates with thionyl chloride-acetic acid — a convenient synthesis of some 1,2-trans-per-O-acetyl-d-glycosyl chlorides