Hang Wei, Li Danyun, Zou Song, Xi Chanjuan
MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
J Org Chem. 2023 Apr 21;88(8):5007-5014. doi: 10.1021/acs.joc.2c01840. Epub 2022 Sep 20.
Cheap and available formate can be seen formally as a carbon dioxide radical anion (CO) combined with a hydrogen atom, where the CO is not only a highly active radical but also a very powerful reductant. In this paper, we successfully realized a visible-light-driven carboxylation of benzyl bromides with carbon dioxide to prepare high-value arylacetic acids using potassium formate as a terminal reductant. This reaction is characterized by mild reaction conditions and a wide range of substrates. Moreover, under nitrogen atmosphere, the reaction can also achieve the carboxylation of benzyl bromides utilizing an excess of potassium formate. Mechanistic experiments indicate this carboxylation proceeded through CO, which was generated from the oxidation of 1,4-diazabicyclo[2.2.2]octane with excited photosensitizer Ir(ppy)(dtbbpy)PF in the presence of the potassium formate.
廉价且易得的甲酸盐可被形式上看作是与一个氢原子结合的二氧化碳自由基阴离子（CO），其中CO不仅是一种高活性自由基，还是一种非常强的还原剂。在本文中，我们成功实现了以甲酸钾作为终端还原剂，通过可见光驱动苄基溴与二氧化碳的羧化反应来制备高价值的芳基乙酸。该反应的特点是反应条件温和且底物范围广泛。此外，在氮气氛围下，使用过量的甲酸钾，该反应也能实现苄基溴的羧化反应。机理实验表明，这种羧化反应是通过CO进行的，CO是在甲酸钾存在的情况下，由激发态光敏剂Ir(ppy)(dtbbpy)PF氧化1,4-二氮杂双环[2.2.2]辛烷生成的。
