2,4,6‐Trimethoxypyridine is identified as an efficient ligand for promoting a Pd‐catalyzed ortho‐CHamination of both benzamides and triflyl‐protected benzylamines. This finding provides guidance for the development of ligands that can improve or enable PdII‐catalyzed CH activation reactions directed by weakly coordinating functional groups.
Pd-Catalyzed Intermolecular C–H Amination with Alkylamines
作者:Eun Jeong Yoo、Sandy Ma、Tian-Sheng Mei、Kelvin S. L. Chan、Jin-Quan Yu
DOI:10.1021/ja202563w
日期:2011.5.25
C-H amination of N-arylbenzamides with O-benzoyl hydroxylamines has been achieved with either Pd(II) or Pd(0) catalysts. Furthermore, we demonstrate that secondary amines can be directly used with benzoyl peroxide in a one-pot procedure that proceeds via the in situ generation of the appropriate O-benzoyl hydroxylamines. This catalytic reaction provides a new disconnection for the convergent synthesis
A Pd(II)-catalyzed trifluoromethylation of ortho C-H bonds with an array of N-arylbenzamides derived from benzoic acids is reported. N-Methylformamide has been identified as a crucial promoter of C-CF3 bond formation from the Pd center. X-ray characterization of the C-H insertion intermediate has revealed a rare coordination mode of acidic amides as directing groups and the origin of their capacity in directing C-H activation.
Ru(II)-Catalyzed <i>ortho</i>-C–H Amination of Arenes and Heteroarenes at Room Temperature
The Rupp-catalyzed ortho-C-H amination directed by a weakly coordinating amide auxiliary with O-benzoyl hydroxylamines at room temperature has been achieved. This reaction is compatible with heterocycles including pyrazole, thiophene, benzothiophene, furan, benzofuran, and indole.
Pd-Catalyzed Oxidative <i>ortho</i>-C–H Borylation of Arenes
作者:Hui-Xiong Dai、Jin-Quan Yu
DOI:10.1021/ja2097095
日期:2012.1.11
The development of a Pd-catalyzed oxidative ortho-C-H borylation with N-arylbenzamides is reported. A modified dibenzylideneacetone (dba) ligand, a weak base, and a strong oxidant are critical for obtaining good yields. The reaction is tolerant of electron-deficient and electron-rich benzamides derived from readily available benzoic acids. The borylated products can be converted to various synthons via diverse transformations.