Geometry-Constrained Iminopyridyl Palladium-Catalyzed Hydroarylation of Alkynes to Prepare Tri-substituted Alkenes Using Alcohol as Reductant
作者:Ke Wu、Nan Sun、Baoxiang Hu、Zhenlu Shen、Liqun Jin、Xinquan Hu
DOI:10.1002/adsc.201800423
日期:2018.8.17
straightforward method to prepare tri‐substituted alkenes through palladium‐catalyzed hydroarylation of alkynes with aryl bromides. Diarylacetylenes and alkyl(aryl)acetylenes could be well hydroarylated with various aryl bromides in moderate to excellent yields. Mechanistic studies suggested that alcohol was the reductant to provide hydride through β‐H elimination. Gram scale reaction further demonstrated
Unusual Formation of Cyclopenta[<i>b</i>]indoles from 3-Indolylmethanols and Alkynes
作者:Soniya Gandhi、Beeraiah Baire
DOI:10.1021/acs.joc.8b03027
日期:2019.4.5
suitable for this transformation. Similarly, N-Ts and N-Boc groups were compatible with reaction conditions, whereas N-Ac and N-Tf failed to undergo this reaction. Isolation of vinyl chloride intermediate suggested the involvement of a vinylic carbocation intermediate. A mechanism has been proposed involving a ring-opening–ring-closing cascade followed by a 1,3-indole migration process via a spirocyclobutene
已经报道了由3-吲哚基甲醇和炔烃酸促进的环戊[ b ]吲哚骨架的合成。整个变换表示通过重新排列而形成的正式[3 + 2]圆环。该方案对甲醇底物和炔烃显示出良好的通用性,并允许生成结构多样的环戊[ b ]吲哚。发现末端炔烃,二烷基取代的内部炔烃和具有电子不足的取代基的炔烃不适合该转化。同样,N -Ts和N -Boc基团与反应条件兼容,而N -Ac和N-Tf未能进行此反应。氯乙烯中间体的分离表明涉及乙烯基碳阳离子中间体。已经提出了一种机制,包括开环-闭环级联反应,然后通过螺环丁烯中间体进行1,3-吲哚迁移过程。
Cross-Coupling of Nonactivated Alkyl Halides with Alkynyl Grignard Reagents: A Nickel Pincer Complex as the Catalyst
作者:Oleg Vechorkin、Aurélien Godinat、Rosario Scopelliti、Xile Hu
DOI:10.1002/anie.201105964
日期:2011.12.2
In a pinch: The nickel pincer complex 1 catalyzes the cross‐coupling of the title compounds with remarkable substrate scope and functional group tolerance. A nickel/alkynyl species was isolated and shown to be catalytically competent. THF=tetrahydrofuran, O‐TMEDA=bis[2‐(N,N‐dimethylaminoethyl)] ether.
Microwave Irradiated Solventless Sonogashira Reaction on Nickel(0) Powder Doped KF/Al<sub>2</sub>O<sub>3</sub>
作者:Min Wang、Pinhua Li、Lei Wang
DOI:10.1081/scc-200026232
日期:2004.1
irradiated solventless Sonogashira coupling reaction catalyzed by nanosize nickel(0) powder on potassium fluoride–alumina mixture has been developed. Terminal alkynes couple with aryl, alkenyl iodide, and aryl bromide in the presence of cuprous iodide, triphenylphosphine, and ultrafine particle nickel(0) on potassium fluoride–alumina to generate the corresponding cross‐coupling products.
On the Regioselectivity of the Nickel-Catalyzed Insertion of Alkynes into the Carbon–Carbon Bond of Oxetan-3-one
作者:Christophe Aïssa、Manuel Barday、Christopher Janot、Daniel Clare、Caitlin Carr-Knox、Bradley Higginson、Kelvin Ho
DOI:10.1055/s-0036-1589052
日期:2017.8
of unsymmetrical alkynes into the carbon–carbonbond of oxetan-3-one in the presence of a nickel catalyst has revealed a strong directing effect of a 2-thienyl substituent. This effect is larger than those of 2-vinylbenzene, trimethylsilyl, aryl, or 3-thienyl groups. The study of the regioselectivity of insertion of unsymmetrical alkynes into the carbon–carbonbond of oxetan-3-one in the presence of