Copper(II)-Catalyzed Conversion of Bisaryloxime Ethers to 2-Arylbenzoxazoles via C−H Functionalization/C−N/C−O Bonds Formation
摘要:
A copper(II)-catalyzed conversion of bisaryloxime ethers to 2-arylbenzoxazoles has been developed. The reaction involves a cascade C H functionalization and C N/C-O bond formation under oxygen atmosphere.
Copper-Mediated Synthesis of Substituted 2-Aryl-N-benzylbenzimidazoles and 2-Arylbenzoxazoles via C–H Functionalization/C–N/C–O Bond Formation
摘要:
An efficient method for the transformation of N-benzyl bisarylhydrazones and bisaryloxime ethers to functionalized 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles is described. The protocol involves a copper(II)-mediated cascade C-H functionalization/C-N/C-O bond formation under neutral conditions. Substrates having either electron-donating or -withdrawing substituents undergo the cyclization to afford the target heterocycles at moderate temperature.
Synthesis of Complex Phenols Enabled by a Rationally Designed Hydroxide Surrogate
作者:Patrick S. Fier、Kevin M. Maloney
DOI:10.1002/anie.201700244
日期:2017.4.10
The conversion of aryl halides to phenols under mild reaction conditions is a longstanding and formidable challenge in organic chemistry. Herein, we report the rational design of a broadly applicable Pd‐catalyzed method to prepare phenols with benzaldehyde oxime as a hydroxide surrogate. These reactions occur under mildly basic conditions and enable the late‐stage hydroxylation of several functionally‐dense
O-Aryloxime Ethers from the Copper(II)-Mediated Cross-Coupling of Oximes and Phenylboronic Acids
作者:Adam Meyer、Abdelselam Ali、Kellie Tuck
DOI:10.1055/s-0028-1088199
日期:2009.4
A direct approach to O-aryloxime ethers by means of the first copper-mediated cross-coupling of aromatic oximes and phenylboronic acids is reported. The O-arylation of acetophenone oximes with phenylboronic acids typically furnished O-aryloxime ethers in good to moderate yields.
Cesium Carbonate Promoted Direct Arylation of Hydroxylamines and Oximes with Diaryliodonium Salts
作者:Yang Yang、Xunshen Wu、Jianwei Han、Song Mao、Xiaofei Qian、Limin Wang
DOI:10.1002/ejoc.201402920
日期:2014.11
A transition-metal-free approach for the arylation of hydroxylamines and oximes with diaryliodonium salts was developed. The reaction proceeded smoothly at room temperature in the presence of cesium carbonate. As a result, a wide range of N- and O-arylated hydroxylamines were synthesized in good to excellent yields (45-98%).
Facile and Metal-Free Synthesis of Phenols from Benzaldoxime and Diaryliodonium Salts
作者:Yongsheng Zhou
DOI:10.3184/174751917x15064232103119
日期:2017.10
A metal-free, base-promoted facile synthesis of phenol derivatives utilising diaryliodonium salts as the aryl source and benzaldoxime as the hydroxide surrogate has been developed. The reaction is fast and shows good substrate compatibility, giving the corresponding products in good to excellent yields. A gram-scale synthesis of phenols utilising this protocol has also been achieved.
Comparison of the kinetics of aldehyde sensing by covalent bond formation with hydrazines and hydroxylamines
作者:Blair K. Troudt、John W. Vue、Philippe Bühlmann
DOI:10.1016/j.tet.2022.132852
日期:2022.7
avoiding use of either aldehyde or probe in a large excess. Hydrazone formation was found to be on average 71 times faster than oxime formation. The rate constants for the reaction of aromatic aldehydes with the phenylhydrazine follow largely the trend predicted by Hammett substituent constants, with the notable exception of the hydrogen bond forming 2-hydroxybenzaldehyde. Unlike in studies with water as
用于检测醛的分析技术通常涉及与肼或羟胺衍生物反应,分别导致形成腙或肟。虽然有各种使用任何一种衍生化试剂的例子,但只有很少的报告有数据适合回答两种类型的探针中的哪一种可以更快和更有选择性地检测醛。针对这个问题,这项工作使用1 H NMR 光谱来研究芳香族和脂肪族醛与两种衍生化探针苯肼或O的反应动力学-苯基羟胺,在四氢呋喃中和在过量的酸催化剂存在下。开发了一种拟合程序来确定这些二级反应的速率常数,同时避免使用大量过量的醛或探针。发现腙形成平均比肟形成快 71 倍。芳香醛与苯肼反应的速率常数在很大程度上遵循 Hammett 取代基常数预测的趋势,但形成氢键的 2-羟基苯甲醛除外。与以水为溶剂的研究不同,没有发现脂肪醛比芳香醛反应更快。