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。
Efficient palladium-catalyzed C(sp<sup>2</sup>)–H activation towards the synthesis of fluorenes
作者:Juan Song、Yali Li、Wei Sun、Chenglong Yi、Hao Wu、Haotian Wang、Keran Ding、Kang Xiao、Chao Liu
DOI:10.1039/c6nj02033j
日期:——
protocol for the synthesis of fluorene derivatives has been developed through palladium-catalyzed cyclization of 2′-halo-diarylmethanes via activation of arylic C–H bonds. The reactions occurred smoothly and allowed both electron-rich and electron-deficient substrates to convert into their corresponding fluorenes in good to excellent yields. Studies revealed that this Pd-catalyzedcyclization was also available
An I2-mediated synthesis of phenanthridines via intramolecular sp3 C-H amination of readily accessible aniline precursors is reported. The present synthetic process is straightforward and applicable to a broad variety of unprotected aniline substrates, and provides facile and efficient access to phenanthridine derivatives. This C-H amination protocol does not use transition metals, is operationally