作者:Yulei Wang、João C. A. Oliveira、Zhipeng Lin、Lutz Ackermann
DOI:10.1002/anie.202016895
日期:2021.3.15
five‐ and six‐membered heterocycles. In contrast, we herein describe the first electrochemical metal‐catalyzed [5+2] cycloadditions to assemble valuable seven‐membered benzoxepine skeletons by C−H/O−H activation. The efficient alkyne annulation featured ample substrate scope, using electricity as the only oxidant. Mechanistic studies provided strong support for a rhodium(III/I) regime, involving a
涉及温和过渡金属催化的 C−H 活化的电氧化环化已成为快速构建五元和六元杂环的变革策略。相比之下,我们在此描述了第一个电化学金属催化的[5+2]环加成反应,通过CH/O-H活化组装有价值的七元苯并氧杂环骨架。高效的炔成环反应具有充足的底物范围,使用电作为唯一的氧化剂。机理研究为铑(III/I)体系提供了强有力的支持,其中涉及苯并氧杂配位的铑(I)夹心络合物作为催化剂静止状态,通过阳极氧化将其重新氧化为铑(III)。