Dimethylzinc‐Initiated Radical Coupling of β‐Bromostyrenes with Ethers and Amines
作者:Amanda Sølvhøj、Andreas Ahlburg、Robert Madsen
DOI:10.1002/chem.201502429
日期:2015.11.2
A new coupling reaction has been developed in which β‐bromostyrenes react with ethers and tertiary amines to introduce the styryl group in the α‐position. The transformation is mediated by Me2Zn/O2 with 10 % MnCl2 and is believed to proceed by a radical addition–elimination mechanism. The ether and the amine are employed as solvent and the coupling takes place through the most stable α radical for unsymmetrical
已开发出一种新的偶联反应,其中β-溴苯乙烯与醚和叔胺反应,在α-位引入苯乙烯基。该转变是由具有10%MnCl 2的Me 2 Zn / O 2介导的,并且据认为是通过自由基加成-消除机理进行的。醚和胺用作溶剂,偶合通过非对称底物的最稳定的α基团发生。获得的产物为纯E异构体,产率中等至良好。可以使用一系列较小的环状和非环状醚/胺以及各种取代的β-溴苯乙烯实现偶联。
Palladium/benzoic acid-catalyzed hydroalkoxylation of alkynes
作者:Isao Kadota、Leopold Mpaka Lutete、Akinori Shibuya、Yoshinori Yamamoto
DOI:10.1016/s0040-4039(01)01207-2
日期:2001.8
The reaction of the internal alkyne 1 with alcohols 2 in the presence of a catalytic amount of Pd(PPh3)4 and benzoic acid in dioxane at 100°C gave the allylic ethers 3 in good to high yields. The reaction proceeds via the palladium/benzoic acid-catalyzedisomerization of the alkyne 1 to allene 6, followed by the addition of alcohols 2 to the π-allylpalladium intermediate 7 formed by the hydropalladation
Improved One-Pot Synthesis of Styryl Tetrahydrofurans and Cyclohexanes by Radical Addition to -Nitrostyrenes in the Presence of Benzoyl Peroxide
作者:Yeong-Jiunn Jang、Yuh-Kuo Shih、Jing-Yuan Liu、Wen-Yu Kuo、Ching-Fa Yao
DOI:10.1002/chem.200204571
日期:2003.5.9
Stereoselective styryl derivatives have been prepared based on radical substitution (addition-elimination) of heterocycles or cyclohydrocarbons units to (E)-beta-nitrostyrenes 1 using a common radical initiator benzoyl peroxide. High reactivity and selectivity with wide substrate scope were attained by using this easy methodology. The reactions using easily obtained and one-pot potential starting materials
Boronic Acid Catalysis as a Mild and Versatile Strategy for Direct Carbo- and Heterocyclizations of Free Allylic Alcohols
作者:Hongchao Zheng、Sina Ghanbari、Shinji Nakamura、Dennis G. Hall
DOI:10.1002/anie.201201620
日期:2012.6.18
BAC to the future: Boronic acid catalysis (BAC) was applied to the direct activation of alcohols leading to the preparation of carbocycles (see scheme), benzofurans, tetrahydrofurans, pyrrolidines, pyrans, piperidines, and various polycyclic compounds. The reactions proceed under mild conditions that circumvent the use of reactive leaving groups like halides.
Radical C(sp<sup>3</sup>)–H alkenylation, alkynylation and allylation of ethers and amides enabled by photocatalysis
作者:Subhasis Paul、Joyram Guin
DOI:10.1039/c7gc00840f
日期:——
enables selective incorporation of alkenyl, alkynyl and allyl functional groups into the C(sp3)–H bond under green reaction conditions is developed. The process is based on the catalytic formation of α-alkoxyl/α-amidyl radicals via the homolytic activation of the C(sp3)–H bond of ethers/amides with a catalytic amount of diarylketone in the presence of a household fluorescent light bulb. This simple reaction