Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
Angew Chem Int Ed Engl. 2022 Apr 25;61(18):e202117233. doi: 10.1002/anie.202117233. Epub 2022 Mar 9.
We report the first example of selective Pd -catalyzed tertiary C-H activation of cyclobutylmethyl ketones using a transient directing group. An electron-deficient 2-pyridone ligand was identified as the optimal external ligand to enable tertiary C-H activation. A variety of cyclobutylmethyl ketones bearing quaternary carbon centers was readily accessed without preinstalling internal directing groups in up to 81 % yield and >95 : 5 regioisomeric ratios of tertiary C-H arylation to β-methylene (β-methyl) or γ-C-H arylation.
我们报告了首例使用瞬态导向基团选择性钯催化环丁基甲基酮的叔 C-H 活化的例子。确定了缺电子的 2-吡啶酮配体作为最佳外部配体，以实现叔 C-H 活化。各种带有季碳原子的环丁基甲基酮在无需预先安装内部导向基团的情况下，以高达 81%的产率和>95:5 的叔 C-H 芳基化与β-亚甲基（β-甲基）或γ-C-H 芳基化的区域异构体比值轻易获得。
