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Electrooxidative Rhodium‐Catalyzed [5+2] Annulations via C−H/O−H Activations
Author(s) -
Wang Yulei,
Oliveira João C. A.,
Lin Zhipeng,
Ackermann Lutz
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202016895
Subject(s) - rhodium , chemistry , catalysis , annulation , alkyne , transition metal , substrate (aquarium) , electrochemistry , platinum , metal , stereochemistry , medicinal chemistry , organic chemistry , electrode , oceanography , geology
Electrooxidative annulations involving mild transition metal‐catalyzed C−H activation have emerged as a transformative strategy for the rapid construction of 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 benzoxepine‐coordinated rhodium(I) sandwich complex as the catalyst resting state, which was re‐oxidized to rhodium(III) by anodic oxidation.