Department of Chemistry, Durham University, South Road, Durham DH1 3LE, UK.
J Org Chem. 2010 Sep 3;75(17):5860-6. doi: 10.1021/jo100877j.
Highly fluorinated nitrobenzene derivatives are suitable substrates for palladium-catalyzed C-F bond arylation using readily available palladium catalysts under both conventional heating and microwave conditions. Arylation occurs ortho to the nitro group offering a synthetic route to polyfluorinated 2-arylnitrobenzene systems. The regiochemistry of the arylation reactions suggests that there is a significant directing interaction between the nitro group and the incoming nucleophilic palladium catalyst which is facilitated by the presence of several fluorine atoms attached the ring. Investigations into the regioselectivity and reactivity of several tetrafluoro- and trifluoronitrobenzene derivatives provides further evidence for the highly nucleophilic character of the oxidative addition step in contrast to the concerted mechanism of more conventional Suzuki-Miyaura coupling reactions involving aryl iodides and bromides.
高度氟化的硝基苯衍生物是适合的钯催化 C-F 键芳基化反应底物，可在常规加热和微波条件下使用易得的钯催化剂进行反应。芳基化反应发生在硝基的邻位，为多氟化 2-芳基硝基苯体系提供了一种合成途径。芳基化反应的区域化学表明，在几个氟原子连接在环上的情况下，硝基和进入的亲核钯催化剂之间存在显著的导向相互作用，这有利于反应的进行。对几种四氟和三氟硝基苯衍生物的区域选择性和反应性的研究进一步证明了氧化加成步骤的高亲核性，与涉及芳基碘化物和溴化物的更传统的 Suzuki-Miyaura 偶联反应的协同机制形成对比。
