Synthetic Applications of Pd(II)-Catalyzed C-H Carboxylation and Mechanistic Insights: Expedient Routes to Anthranilic Acids, Oxazolinones, and Quinazolinones
Synthetic Applications of Pd(II)-Catalyzed C-H Carboxylation and Mechanistic Insights: Expedient Routes to Anthranilic Acids, Oxazolinones, and Quinazolinones
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DOI：
10.1021/ja9077705
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发表时间：
2010-01-20
影响因子：
15
通讯作者：
Yu, Jin-Quan
中科院分区：
文献类型：
--
作者：
Giri, Ramesh;Lam, Jonathan K.;Yu, Jin-Quan
研究了Pd（II）催化苯胺邻位C-H键羧化生成N-酰基邻氨基苯甲酸的反应。该反应过程提供了一种新的和有效的策略，用于从简单的苯胺快速组装生物学和药学上重要的分子，如苯并恶嗪酮和喹唑啉酮，而无需安装和移除外部导向基团。反应条件也适合于N-苯基吡咯烷酮的羧化。用X-射线晶体学方法研究了一种含对甲苯磺酸盐阴离子配体的钯配合物，并讨论了对甲苯磺酸在一氧化碳存在下活化C-H键的关键作用。两个关键的中间体，混合酸酐和苯并恶嗪酮形成的有机金属Ar（CO）Pd（II）-OTs物种的还原消除的鉴定，提供了一个双反应途径的机理证据。
A Pd(II)-catalyzed reaction protocol for the carboxylation of ortho-C-H bonds in anilides to form N-acyl anthranilic acids has been developed. This reaction procedure provides a novel and efficient strategy for the rapid assembly of biologically and pharmaceutically significant molecules, such as benzoxazinones and quinazolinones, from simple anilides without installing and removing an external directing group. The reaction conditions are also amenable to the carboxylation of N-phenyl pyrrolidinones. A monomeric palladacycle containing p-toluenesulfonate as an anionic ligand has been characterized by X-ray crystallography, and the crucial role of p-toluenesulfonic acid in the activation of C-H bonds in the presence of carbon monoxide is discussed. Identification of two key intermediates, a mixed anhydride and benzoxazinone formed by reductive elimination from organometallic Ar(CO)Pd(II)-OTs species, provides mechanistic evidence for a dual-reaction pathway.