Synthesis of 5-Iodopyrrolo[1,2-a]quinolines and Indolo[1,2-a]quinolines via Iodine-Mediated Electrophilic and Regioselective 6-endo-dig Ring Closure
摘要:
The endo-cyclic ring closure of 1-(2-(substituted ethynyl)pheny1)-1H-pyrroles 3a-t and 1-(2-(substituted ethynyl)phenyl)-H-indole 4a-o mediated by Lewis acid (I-2) under mild conditions afforded substituted 5-iodopyrrolo[1,2-a]quinolines 5a-t and 5-iodoindolo[1,2-a]quinolines 6a-o in good to excellent yields. The reaction shows selective C-C bond formation on the more electrophilic alkynyl carbon, resulting in the regioselective 6-endo-dig-cyclized product. Iodo derivatives of pyrrolo- and indoloquinolines allow functional group diversification on the quinoline nucleus, which proves to be highly advantageous for structural and biological activity assessments.
carbonylation reaction for the synthesis of fluoren‐9‐ones from 2‐halogenated biphenyls using phenyl formate as a carbon monoxide surrogate was achieved. The combined use of cesium carbonate and o‐anisic acid resulted in a remarkable rate enhancement, where the reaction was complete within 3 min in some cases. Mechanistic studies indicated that the turnover‐limiting step of the reaction was the C−H bond‐cleaving
A highly efficient palladium‐catalyzed disilylation reaction of arylhalides through C−H activation has been developed for the first time. The reaction has broad substrate scope. A variety of arylhalides can be disilylated by three types of C−H activation, including C(sp2)−H, C(sp3)−H, and remote C−H activation. In particular, the reactions are also unusually efficient. The yields are essentially
reaction for N-substituted pyrrole synthesis using 2,5-dimethoxytetrahydrofuran with variously substituted aromatic amines has been developed (up to 89% yield). This interesting neat strategy is free from additives including co-catalysts, ligands, and acids. Relatively low cost, environmentally benign, and handy Mn(NO3)2·4H2O is employed as the catalyst undermicrowave conditions with a very short reaction
Highly Efficient Route to Fused Polycyclic Aromatics via Palladium-Catalyzed Aryne Annulation by Aryl Halides
作者:Zhijian Liu、Richard C. Larock
DOI:10.1021/jo0619534
日期:2007.1.1
Polycyclic aromatic and heteroaromatic hydrocarbons have been synthesized in high yield by two different processes involving the Pd-catalyzed annulation of arynes. The first process involves a Pd-catalyzed annulation of arynes by 2-halobiaryls and related vinylic halides. The second process utilizes a Pd-catalyzed double annulation of arynes by simple aryl halides. Both processes appear to involve
Expeditious Synthesis of Tetrasubstituted Helical Alkenes by a Cascade of Palladium-Catalyzed CH Activations
作者:Hongqiang Liu、Mohamed El-Salfiti、Mark Lautens
DOI:10.1002/anie.201204226
日期:2012.9.24
Twisted molecules: A modular approach for the synthesis of tetrasubstitutedhelicalalkenes by a palladium‐catalyzed norbornene‐mediated domino reaction is presented. This intermolecular domino process allows the formation of three CC bonds in one operation through a CH activation/carbopalladation/CH activation sequence.
扭曲分子:提出了一种通过钯催化的降冰片烯介导的多米诺反应合成四取代螺旋烯烃的模块化方法。此分子间多米诺过程允许的三个C的形成在一个操作中C键通过C ħ激活/ carbopalladation / C ħ激活序列。