Carbonates: eco-friendly solvents for palladium-catalysed direct arylation of heteroaromatics
作者:Jia Jia Dong、Julien Roger、Cécile Verrier、Thibaut Martin、Ronan Le Goff、Christophe Hoarau、Henri Doucet
DOI:10.1039/c0gc00229a
日期:——
The palladium-catalyseddirect2-, 4- or 5-arylation of a wide range of heteroaromatics with aryl halides proceed in moderate to good yields using the eco-friendly solvents carbonates. The best yields were obtained using benzoxazole or thiazole derivatives. The arylation of furan, thiophene, pyrrole, imidazole or isoxazole derivatives was found to require a more elevated reaction temperature.
PdCl(dppb)(C3H5) as a catalyst, a range of heteroaryl derivatives undergoes coupling via C–Hbondactivation/functionalization reaction with chloropyridines or chloroquinolines in low to high yields. This air-stable catalyst can be used with a wide variety of substrates. The position of the chloro substituent on pyridines has a minor influence on the yields. On the other hand, the nature on the heteroaryl derivative
芳基氯化物与杂芳烃的直接偶联将具有可持续发展的巨大优势,因为它们的成本更低,质量更轻,可用化合物的多样性更大,并且还因为仅形成了与副产物碱有关的HCl和减少制备这些化合物的步骤数。我们观察到通过使用PdCl(dppb)(C 3 H 5)作为催化剂,一系列杂芳基衍生物通过C–H键活化/官能化反应与氯吡啶或氯喹啉进行低至高收率的偶联。这种空气稳定的催化剂可与多种基材一起使用。吡啶上氯取代基的位置对收率影响很小。另一方面,杂芳基衍生物的性质具有很大的影响。使用苯并恶唑,噻吩或噻唑衍生物可获得最高的收率。氯吡啶与呋喃的偶联也得到了预期的产物,但是产率低至中等。
Palladium-catalysed direct arylations of heteroaromatics using more eco-compatible solvents pentan-1-ol or 3-methylbutan-1-ol
作者:Souhila Bensaid、Nouria Laidaoui、Douniazad El Abed、Soufi Kacimi、Henri Doucet
DOI:10.1016/j.tetlet.2011.01.084
日期:2011.3
The palladium-catalysed direct coupling of aryl halides with heteroaromatics in greener solvents than DMF or DMAc, which are often employed for such couplings, would be a considerable advantage for both industrial application and sustainable development. We observed that a range of aryl bromides undergoe coupling via C-H bond activation/functionalisation reaction of thiazoles or imidazoles in moderate to good yields using pentan-1-ol or 3-methylbutan-1-ol as the solvents. Pentan-1-ol and 3-methylbutan-1-ol are less toxic than DMF or DMAc, moreover they are bioresources as they can be obtained by fermentation. Therefore, these reaction conditions are certainly more eco-compatible than those generally employed for such couplings. (C) 2011 Elsevier Ltd. All rights reserved.
Solvent-Free Palladium-Catalyzed Direct Arylation of Heteroaromatics with Aryl Bromides
作者:Souhila Bensaid、Henri Doucet
DOI:10.1002/cssc.201100771
日期:2012.8
course of catalyzed directarylations. Some palladium‐catalyzed directarylations of heteroaromatics can be advantageously performed without any solvent. In the presence of palladiumcatalysts (1 mol %) and potassium acetate as the base, the direct 5‐arylation of some thiazoles, thiophenes, furans, or pyrroles with arylbromides as coupling partners proceeds highly regioselectively and in moderate to