Ligand-Free-Palladium-Catalyzed Direct 4-Arylation of Isoxazoles Using Aryl Bromides
作者:Yacoub Fall、Céline Reynaud、Henri Doucet、Maurice Santelli
DOI:10.1002/ejoc.200900309
日期:2009.8
palladium-catalysed C–H bond activation/arylation of 3,5-disubstituted isoxazoles using aryl or heteroaryl bromides. Good yields were generally obtained by using 0.1–0.5 mol-% of the air-stable PdCl2 complex as the catalyst. A range of functional groups such as acetyl, formyl, ester, fluoro, nitro, trifluoromethyl or nitrile on the aryl bromide is tolerated. This reaction is environmentally attractive, as the
4-芳基异恶唑可以很容易地通过钯催化的 C-H 键活化/使用芳基或杂芳基溴化物对 3,5-二取代异恶唑进行芳基化来制备。通常使用 0.1-0.5 mol% 的空气稳定 PdCl2 配合物作为催化剂可以获得良好的产率。允许芳基溴上的一系列官能团,例如乙酰基、甲酰基、酯、氟、硝基、三氟甲基或腈。该反应对环境具有吸引力,因为主要废物是 KBr/AcOH,而不是传统交叉偶联过程中产生的金属盐。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)