TY - JOUR
T1 - Csp2-H Amination Reactions Mediated by Metastable Pseudo-Oh Masked Aryl-CoIII-nitrene Species
AU - Capdevila, Lorena
AU - Montilla, Marc
AU - Planas, Oriol
AU - Brotons, Artur
AU - Salvador, Pedro
AU - Martin-Diaconescu, Vlad
AU - Parella, Teodor
AU - Luis, Josep M.
AU - Ribas, Xavi
N1 - Funding Information:
This work was financially supported by MICINN (CTQ2016-77989-P and PID2019-104498GB-I00 to X.R., PGC2018-098212-B-C22 to J.M.L. and PGC2018-095808-B-I00 to T.P.) and Generalitat de Catalunya (2017SGR264 to X.R. and 2017SGR39 to J.M.L.). X.R. is thankful for an ICREA Academia award. X-ray absorption experiments were performed at the CLAESS beamline at ALBA Synchrotron with the collaboration of ALBA staff (V.M.-D.) as part of the in-house experiment 2019093969. We thank Dr. A. Company for fruitful discussions and STR-UdG for technical support.
Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.
PY - 2022
Y1 - 2022
N2 - Cobalt-catalyzed C-H amination via M-nitrenoid species is spiking the interest of the research community. Understanding this process at a molecular level is a challenging task, and here we report a well-defined macrocyclic system featuring a pseudo-Oh aryl-CoIII species that reacts with aliphatic azides to effect intramolecular Csp2-N bond formation. Strikingly, a putative aryl-CoNR nitrenoid intermediate species is formed and is rapidly trapped by a carboxylate ligand to form a carboxylate masked-nitrene, which functions as a shortcut to stabilize and guide the reaction to productive intramolecular Csp2-N bond formation. On one hand, several intermediate species featuring the Csp2-N bond formed have been isolated and structurally characterized, and the essential role of the carboxylate ligand has been proven. Complementarily, a thorough density functional theory study of the Csp2-N bond formation mechanism explains at the molecular level the key role of the carboxylate-masked nitrene species, which is essential to tame the metastability of the putative aryl-CoIIINR nitrene species to effectively yield the Csp2-N products. The solid molecular mechanistic scheme determined for the Csp2-N bond forming reaction is fully supported by both experimental and computation complementary studies.
AB - Cobalt-catalyzed C-H amination via M-nitrenoid species is spiking the interest of the research community. Understanding this process at a molecular level is a challenging task, and here we report a well-defined macrocyclic system featuring a pseudo-Oh aryl-CoIII species that reacts with aliphatic azides to effect intramolecular Csp2-N bond formation. Strikingly, a putative aryl-CoNR nitrenoid intermediate species is formed and is rapidly trapped by a carboxylate ligand to form a carboxylate masked-nitrene, which functions as a shortcut to stabilize and guide the reaction to productive intramolecular Csp2-N bond formation. On one hand, several intermediate species featuring the Csp2-N bond formed have been isolated and structurally characterized, and the essential role of the carboxylate ligand has been proven. Complementarily, a thorough density functional theory study of the Csp2-N bond formation mechanism explains at the molecular level the key role of the carboxylate-masked nitrene species, which is essential to tame the metastability of the putative aryl-CoIIINR nitrene species to effectively yield the Csp2-N products. The solid molecular mechanistic scheme determined for the Csp2-N bond forming reaction is fully supported by both experimental and computation complementary studies.
UR - http://www.scopus.com/inward/record.url?scp=85137164226&partnerID=8YFLogxK
U2 - https://doi.org/10.1021/acs.inorgchem.2c02111
DO - https://doi.org/10.1021/acs.inorgchem.2c02111
M3 - Article
C2 - 35997604
AN - SCOPUS:85137164226
ER -