Nickel-Catalyzed Radical Migratory Coupling Enables C-2 Arylation of Carbohydrates
作者:Gaoyuan Zhao、Wang Yao、Ilia Kevlishvili、Jaclyn N. Mauro、Peng Liu、Ming-Yu Ngai
DOI:10.1021/jacs.1c03563
日期:2021.6.16
concerted 1,2-acyloxy rearrangement via a cyclic five-membered-ring transition state followed by nickel-catalyzed carbon–carbonbond formation. The novel reactivity provides an efficient route to valuable C-2-arylated carbohydrate mimics and building blocks, allows for new strategic bond disconnections, and expands the reactivity profile of nickel catalysis.
Efficient synthesis of β-(1,6)-linked oligosaccharides through microwave-assisted glycosylation
作者:Lingyao Li、Emily A. Franckowiak、Yi Xu、Evan McClain、Wenjun Du
DOI:10.1002/pola.26771
日期:2013.9.1
oligosaccharides. Di‐functional AB monomers, 2,3,4‐tri‐O‐acetyl‐α‐d‐galactopyranosyl bromide (3a) and 2,3,4‐tri‐O‐acetyl‐α‐d‐glucopyranosyl bromide (3b) were designed and synthesized as weakly reactive monomers to avoid unwanted glycosylation or degradation during preparation and storage. The glycosylations of these monomers gave low conversions and low molecular weight oligosaccharides at rt, reflux, and
palladium catalysis has emerged as a promising strategy for developing novel and valuable reactions. Herein, we report the first excited-state Pd-catalyzed 1,2-radical migratory Mizoroki–Heckreaction that enables C2-alkenylation of carbohydrates using readily available 1-bromosugars and alkenes. The reaction tolerates a wide variety of functional groups and complex molecular architectures, including
Solvent and α-secondary kinetic isotope effects on β-glucosidase
作者:Miaomiao Xie、Larry D. Byers
DOI:10.1016/j.bbapap.2015.02.015
日期:2015.11
constants for the partitioning (between water and various alcohols) of the glucosyl-enzyme intermediate, coupled with the rate constants for the forward (hydrolysis) reaction provide an estimate of the stability of the glucosyl-enzyme intermediate. This is a relatively stable species with an energy about 2 to 4 kcal/mol higher than that of the ES complex. This article is part of a Special Issue entitled:
From Glucose to Polymers: A Continuous Chemoenzymatic Process
作者:Sampa Maiti、Saikat Manna、Nicholas Banahene、Lucynda Pham、Zhijie Liang、Jun Wang、Yi Xu、Reuben Bettinger、John Zientko、Aaron P. Esser‐Kahn、Wenjun Du
DOI:10.1002/anie.202006468
日期:2020.10.19
Efforts to synthesize degradablepolymersfromrenewableresources are deterred by technical and economic challenges; especially, the conversion of natural building blocks into polymerizable monomers is inefficient, requiring multistep synthesis and chromatographic purification. Herein we report a chemoenzymatic process to address these challenges. An enzymatic reaction system was designed that allows