Copper-mediated anomeric <i>O</i>-arylation with organoboron reagents
作者:Victoria Dimakos、Jacklyn J. W. Liu、Zhenlu Ge、Mark S. Taylor
DOI:10.1039/c9ob01022j
日期:——
Copper-mediated couplings of arylboroxines with glycosyl hemiacetals furnish O-aryl glycosides via Csp2-O bond formation. The method enables the anomeric O-arylation of protected pyranose and furanose derivatives, and is tolerant of functionalized arylboroxine partners. Whereas mixtures of anomers are formed from glucopyranose, galactopyranose and arabinofuranose hemiacetals, the α-anomer is generated
Stereoselective β-mannosylations and β-rhamnosylations from glycosyl hemiacetals mediated by lithium iodide
作者:Imlirenla Pongener、Dionissia A. Pepe、Joseph J. Ruddy、Eoghan M. McGarrigle
DOI:10.1039/d1sc01300a
日期:——
Stereoselective β-mannosylation is one of the most challenging problems in the synthesis of oligosaccharides. Herein, a highly selective synthesis of β-mannosides and β-rhamnosides from glycosyl hemi-acetals is reported, following a one-pot chlorination, iodination, glycosylation sequence employing cheap oxalyl chloride, phosphine oxide and LiI. The present protocol works excellently with a wide range
立体选择性β-甘露糖基化是寡糖合成中最具挑战性的问题之一。在此,报道了使用廉价的草酰氯、氧化膦和 LiI 进行一锅氯化、碘化、糖基化序列后,从糖基半缩醛中高度选择性地合成 β-甘露糖苷和 β-鼠李糖苷。本协议适用于广泛的糖基受体和武装糖基供体。该方法不需要构象限制的供体或导向基团;建议观察到的高β-选择性是通过碘化锂促进的 α-糖基碘化物的 S N 2 型反应实现的。
Glycosylidene Carbenes. Part 2. Synthesis ofO-Aryl Glycosides
作者:Karin Briner、Andrea Vasella
DOI:10.1002/hlca.19900730621
日期:1990.9.19
Phenol, 4-methoxyphenol, 4-nitrophenol, methyl orsellinate (1), and 2,6-di(tert-butyl)-4-methylphenol (BHT; 2) have been glycosylated by thermal reaction (20–60°) with various glycosylidene-derived diazirines.