1510865-07-2Relevant academic research and scientific papers
Practical, Large-Scale Preparation of Benzoxepines and Coumarins through Rhodium(III)-Catalyzed C-H Activation/Annulation Reactions
Gulías, Moisés,Marcos-Atanes, Daniel,Mascare?as, José L.,Font, Marc
, p. 1669 - 1673 (2019)
Herein we disclose the assembly of benzoxepines and coumarins from 2-alkenylphenol precursors using [Cp*RhCl2]2 as the precatalyst and alkynes or carbon monoxide as reacting partners. The preparation of benzoxepines and coumarins can be scaled up to 33 mmol using low catalyst loadings.
Electrooxidative Rhodium-Catalyzed [5+2] Annulations via C?H/O?H Activations
Wang, Yulei,Oliveira, Jo?o C. A.,Lin, Zhipeng,Ackermann, Lutz
supporting information, p. 6419 - 6424 (2021/02/16)
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.
Straightforward assembly of benzoxepines by means of a rhodium(III)- catalyzed C-H functionalization of o-vinylphenols
Seoane, Andres,Casanova, Noelia,Quinones, Noelia,Mascarenas, Jose L.,Gulias, Moises
supporting information, p. 834 - 837 (2014/02/14)
Readily available o-vinylphenols undergo a formal (5 + 2) cycloaddition to alkynes when treated with catalytic amounts of [Cp*RhCl2] 2 and Cu(OAc)2. The reaction, which involves the cleavage of the terminal C-H bond of the alkenyl moiety, generates highly valuable benzoxepine skeletons in a practical, versatile, and atom-economical manner. Using carbon monoxide instead of an alkyne as reaction partner leads to coumarin products which formally result from a (5 + 1) cycloaddition.
