Electrooxidative Rhodium-Catalyzed [5+2] Annulations via C-H/O-H Activations.
Angew Chem Int Ed Engl
; 60(12): 6419-6424, 2021 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-33471952
ABSTRACT
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.
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MEDLINE
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En
Ano de publicação:
2021
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Article