Khake Shrikant M, Soni Vineeta, Gonnade Rajesh G, Punji Benudhar
Organometallic Synthesis and Catalysis Group, Chemical Engineering Division, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, Maharastra, India.
Centre for Material Characterization, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, Maharastra, India.
Chemistry. 2017 Feb 24;23(12):2907-2914. doi: 10.1002/chem.201605306. Epub 2017 Jan 27.
A general nickel-catalyzed method for the alkynylation of heteroarenes through monodentate chelation assistance is described. Many heterocycles, including indoles, pyrroles, imidazoles, and pyrazole, efficiently coupled with (triisopropylsilyl)alkynyl bromide, and synthetically important functional groups, such as halides, ether, nitrile, and nitro, are tolerated. Synthetic applicability of this Ni-catalyzed method is demonstrated by the removal of the triisopropylsilyl group and further functionalization to triazolyl, benzofuranyl, and alkynyl arene derivatives. Preliminary mechanistic investigations of the alkynylation of indole suggest that the reaction proceeds through kinetically relevant C-H activation and follows a two-electron redox pathway. A catalytically relevant Ni species, namely, [(Phen) Ni]NiBr (PheN=1,10-phenanthroline), was isolated and structurally characterized.
本文描述了一种通过单齿螯合辅助实现杂芳烃炔基化的通用镍催化方法。许多杂环化合物，包括吲哚、吡咯、咪唑和吡唑，都能与（三异丙基硅基）炔基溴高效偶联，并且卤化物、醚、腈和硝基等具有重要合成意义的官能团也能耐受。通过去除三异丙基硅基并进一步官能化制备三唑基、苯并呋喃基和炔基芳烃衍生物，证明了这种镍催化方法的合成适用性。对吲哚炔基化的初步机理研究表明，该反应通过动力学相关的C-H活化进行，并遵循双电子氧化还原途径。分离并对一种催化相关的镍物种，即[(Phen)Ni]NiBr（PheN = 1,10 - 菲咯啉）进行了结构表征。
