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。
Cyclopentyl Methyl Ether: An Alternative Solvent for Palladium-Catalyzed Direct Arylation of Heteroaromatics
作者:Kassem Beydoun、Henri Doucet
DOI:10.1002/cssc.201000405
日期:2011.4.18
Some ethers, such as cyclopentyl methylether and di‐n‐butyl ether, which can be considered as “greener” solvents than N,N‐dimethylacetamide (DMAc) or DMF, can be advantageously employed for the palladium‐catalyzed direct arylation of heteroaromatics. In the presence of such ethers and only 0.5–1 mol % of palladium catalysts at 125–150 °C, the direct 5‐arylation of thiazoles, thiophenes, or furans
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。