电催化已被认为是有机金属催化的有力策略,但是电催化CH活化仅限于强N配位的导向基团。给出了通过弱O配位进行电催化C-H活化的第一个例子,其中通用的羧酸钌(II)催化剂可在没有金属氧化剂的情况下实现炔烃环化的电氧化C / H / OH功能化。从而利用可持续的电力作为唯一的氧化剂。机械学的见解为简便的有机金属CH钌钌化和关键钌(0)中间体的有效电化学再氧化提供了有力的支持。
A Strategy for Site‐ and Chemoselective C−H Alkenylation through Osmaelectrooxidative Catalysis
作者:Isaac Choi、Antonis M. Messinis、Xiaoyan Hou、Lutz Ackermann
DOI:10.1002/anie.202110616
日期:2021.12.20
The first osmium-catalyzed electrooxidative C−H annulation is disclosed. While improved selectivities are possible, unprecedented osmium intermediates are presented along with detailed kinetic studies, which revealed the working mode of osmaelectrocatalysis.
An inexpensive cationic ruthenium(II) catalyst enabled the expedient synthesis of isocoumarins through oxidative annulations of alkynes by benzoic acids. This C-H/O-H bond functionalization process also proved applicable to the preparation of alpha-pyrones and was shown to proceed by rate-limiting C-H bond ruthenation.