Synthesis of Methylene-Bridge Polyarenes through Palladium-Catalyzed Activation of Benzylic Carbon-Hydrogen Bond
作者:Chien-Chi Hsiao、Yi-Kuan Lin、Chia-Ju Liu、Tsun-Cheng Wu、Yao-Ting Wu
DOI:10.1002/adsc.201000651
日期:2010.12.17
In the presence of palladium(II) acetate [Pd(OAc)2] and an N-heterocyclic carbene (NHC) ligand, fluorene derivatives can be generated in good to excellent yields from 2-halo-2′-methylbiaryls through the benzylic CH bond activation (14 examples; 81–97% yields). The scope and limitations of this protocol have been examined. A wide range of functional groups, such as alkyl, alkoxy, ester, nitrile, and
在乙酸钯(II)[Pd(OAc)2 ]和N-杂环卡宾(NHC)配体的存在下,芴衍生物可以从2-卤代2'-甲基联芳基通过苄基CH生成高至极好的收率键活化(14个例子;产率81-97%)。已经检查了该协议的范围和局限性。各种各样的官能团,例如烷基,烷氧基,酯,腈和其他,能够耐受本文的反应条件。同位素标记的联苯的环化反应产生相应的产物,具有主要的动力学同位素效应(k H / k D= 4.8∶1),这表明该反应的决定速率的步骤是苄基CH键的活化。此外,从三联苯中也获得了茚并芴的优异结果(3个实例;产率为91-92%)。2,6-二氯-2'-甲基联苯与二苯乙炔的级联反应通过芳基和苄基CH键的活化,以60%的收率产生了8,9-二苯基-4 H-环戊[ def ]菲。