Palladium-catalyzed Mizoroki–Heck reactions were carried out in the presence of calcium carbonate in alcoholic solvents. Under these conditions an efficient preparation of functionalized benzalacetones was developed. The reactions were carried out at room temperature and aerobic conditions, giving the products within several minutes in up to 95% isolated yields. Furthermore, some kinetic investigations
[3 + 2] Cycloaddition of Isocyanides with Aryl Diazonium Salts: Catalyst-Dependent Regioselective Synthesis of 1,3- and 1,5-Disubstituted 1,2,4-Triazoles
作者:Jian-Quan Liu、Xuanyu Shen、Yihan Wang、Xiang-Shan Wang、Xihe Bi
DOI:10.1021/acs.orglett.8b03069
日期:2018.11.2
An unprecedented catalyst-dependent regioselective [3 + 2] cycloaddition of isocyanides with aryl diazonium salts is reported. 1,3-Disubstituted 1,2,4-triazoles were selectively obtained in high yield under Ag(I) catalysis, whereas 1,5-disubstituted 1,2,4-triazoles were formed by Cu(II) catalysis. These catalytic methodologies provide a controlled, modular, and facile access to 1,2,4-triazole scaffolds
Gold(<scp>i</scp>)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes
作者:Manjur O. Akram、Popat S. Shinde、Chetan C. Chintawar、Nitin T. Patil
DOI:10.1039/c8ob00630j
日期:——
Gold(I)-catalyzed cross-couplingreactions of aryldiazonium salts with organostannanes are described. This redox neutral strategy offers an efficient approach to diverse biaryls, vinyl arenes and arylacetylenes. Monitoring the reaction with NMR and ESI-MS provided strong evidence for the in situ formation of Ph3PAuIR (R = aryl, vinyl and alkynyl) species which is crucial for the activation of aryldiazonium
描述了金(I)催化的芳基重氮盐与有机锡烷的交叉偶联反应。这种氧化还原中性策略为各种联芳基,乙烯基芳烃和芳基乙炔提供了一种有效的方法。用NMR和ESI-MS监测反应为原位形成Ph 3 PAu I R(R =芳基,乙烯基和炔基)物种提供了有力证据,这对于激活芳基重氮盐至关重要。
A general electrochemical strategy for the Sandmeyer reaction
Herein we report a general electrochemical strategy for the Sandmeyer reaction. Using electricity as the driving force, this protocol employs a simple and inexpensive halogen source, such as NBS, CBrCl3, CH2I2, CCl4, LiCl and NaBr for the halogenation of aryl diazonium salts. In addition, we found that these electrochemical reactions could be performed using anilines as the starting material in a one-pot
本文中,我们报告了桑德迈尔反应的一般电化学策略。使用电作为驱动力,该协议采用一种简单且廉价的卤素源,例如NBS,CBrCl 3,CH 2 I 2,CCl 4,LiCl和NaBr进行芳基重氮盐的卤化。另外,我们发现这些电化学反应可以以一锅的方式使用苯胺作为起始原料来进行。此外,该方法的实用性在使用非常便宜的石墨作为电极的多克规模的芳基卤化物的合成中得到了证明。已经进行了一系列详细的机理研究,包括自由基时钟和自由基清除剂研究,循环伏安分析和原位电子顺磁共振(EPR)分析。
LIC-KOR promoted formation of conjugated dienes as useful building blocks for palladium-catalyzed syntheses
作者:Annamaria Deagostino、Manuele Migliardi、Ernesto G. Occhiato、Cristina Prandi、Chiara Zavattaro、Paolo Venturello
DOI:10.1016/j.tet.2005.01.044
日期:2005.3
It is demonstrated that α,β-unsaturated acetals can be considered a synthetic tool for transforming carbonyl derivatives into cheap and easily accessible starting materials for the construction of various and more complex structures. The lithium–potassium mixed superbase LIC-KOR induces a conjugate elimination reaction that converts α,β-unsaturated acetals into 1E-1-alkoxybuta-1,3-dienes. These derivatives
已经证明,α,β-不饱和缩醛可以被认为是用于将羰基衍生物转化成廉价且易于获得的起始材料以用于构建各种和更复杂的结构的合成工具。锂-钾混合超碱LIC-KOR引起共轭消除反应,该反应将α,β-不饱和缩醛转化为1 E -1-烷氧基丁1,3-二烯。这些衍生物可以很容易地就地金属化并通过与亲电试剂反应而官能化。结果可分为两部分:(1)烷氧基二烯基硼酸酯与四氢萘醌或异苯并二氢吡喃酮衍生的乙烯基三氟甲磺酸酯之间的钯催化交叉偶联反应;(2)在钯催化剂的存在下与芳基衍生物的区域和立体选择性交叉偶联反应(Heck条件)。