Ni Shengyang, Spinnato Davide, Cornella Josep
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, 45470, Germany.
J Am Chem Soc. 2024 Aug 14;146(32):22140-22144. doi: 10.1021/jacs.4c07262. Epub 2024 Aug 5.
We present here a catalytic method based on a low-valent Bi complex capable of cyclopropanation of double bonds under blue LED irradiation. The catalysis features various unusual Bi-based organometallic steps, namely, (1) two-electron inner sphere oxidative addition of Bi(I) complex to CHI, (2) light-induced homolysis of the Bi(III)-CHI bond, (3) subsequent iodine abstraction-ring-closing, and (4) reduction of Bi(III) to Bi(I) with an external reducing agent to close the cycle. Stoichiometric organometallic experiments support the proposed mechanism. This protocol represents a unique example of a reductive photocatalytic process based on low-valent bismuth radical catalysis.
我们在此展示一种基于低价铋配合物的催化方法，该方法能够在蓝色发光二极管照射下实现双键的环丙烷化反应。该催化反应具有各种不同寻常的铋基有机金属步骤，即：(1) Bi(I)配合物对CHI进行双电子内球氧化加成；(2)光致Bi(III)-CHI键均裂；(3)随后的碘原子夺取-环化反应；(4)用外部还原剂将Bi(III)还原为Bi(I)以完成催化循环。化学计量的有机金属实验支持了所提出的机理。该方案是基于低价铋自由基催化的还原光催化过程的一个独特例子。
