Isolation of Key Organometallic Aryl-Co(III) Intermediates in Cobalt- Catalyzed C(sp2)−H Functionalizations and New Insights into Alkyne Annulation Reaction Mechanisms
dc.contributor.author
dc.date.accessioned
2017-03-03T09:39:48Z
dc.date.available
2017-03-03T09:39:48Z
dc.date.issued
2016-10-10
dc.identifier.issn
0002-7863
dc.identifier.uri
dc.description.abstract
The selective annulation reaction of alkynes with substrates containing inert C-H bonds using cobalt as catalyst is currently a topic attracting significant interest. Unfortunately, the mechanism of this transformation is still relatively poorly understood, with little experimental evidence for intermediates, although an organometallic Co(III) species is generally implicated. Herein, we describe a rare example of the preparation and characterization of benchtop-stable organometallic aryl-Co(III) compounds (NMR, HRMS, XAS, and XRD) prepared through a C(sp2)-H activation, using a model macrocyclic arene substrate. Furthermore, we provide crystallographic evidence of an organometallic aryl-Co(III) intermediate proposed in 8-aminoquinoline-directed Co-catalyzed C-H activation processes. Subsequent insights obtained from the application of our new organometallic aryl-Co(III) compounds in alkyne annulation reactions are also disclosed. Evidence obtained from the resulting regioselectivity of the annulation reactions and DFT studies indicates that a mechanism involving an organometallic aryl-Co(III)-alkynyl intermediate species is preferred for terminal alkynes, in contrast to the generally accepted migratory insertion pathway
dc.description.sponsorship
We acknowledge financial support from the European Research Council for the Starting Grant Project ERC-2011-StG-277801 to X.R. and from MINECO of Spain for project CTQ2013-43012-P to A.C. and X.R., CTQ2014-52525-P to J.M.L and CTQ2015-64436-P to T.P. We also thank Generalitat de Catalunya for projects 2014SGR862 and 2014SGR931. We thank the MECD of Spain for a FPU PhD grant to O.P. and MINECO for a Ramón y Cajal contract to A.C. X.R. also thanks Generalitat de Catalunya for an ICREA-Acadèmia Award. In addition, the research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312284
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
American Chemical Society
dc.relation
info:eu-repo/grantAgreement/MINECO//CTQ2013-43012-P/ES/INVESTIGACIONES MECANISTICAS PARA SINTESIS ORGANICA SOSTENIBLE VIA ACTIVACION DE PEQUEÑAS MOLECULAS GASEOSAS Y DE ENLACES C-H CON METALES DE LA PRIMERA SERIE DE TRANSICION/
info:eu-repo/grantAgreement/MINECO//CTQ2014-52525-P/ES/FUNCIONALES DFT PARA EL CALCULO DE PROPIEDADES OPTICAS NO LINEALES/
dc.relation.isformatof
Reproducció digital del document publicat a: http://dx.doi.org/10.1021/jacs.6b08593
dc.relation.ispartof
© Journal of the American Chemical Society, 2016, vol. 138, núm. 43, p. 14388-14397
dc.relation.ispartofseries
Articles publicats (D-Q)
dc.rights
Tots els drets reservats
dc.title
Isolation of Key Organometallic Aryl-Co(III) Intermediates in Cobalt- Catalyzed C(sp2)−H Functionalizations and New Insights into Alkyne Annulation Reaction Mechanisms
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/embargoedAccess
dc.embargo.terms
Cap
dc.date.embargoEndDate
info:eu-repo/date/embargoEnd/2026-01-01
dc.relation.projectID
info:eu-repo/grantAgreement/EC/FP7/277801/EU/Sustainable C-X and C-H Functionalization Catalyzed by Copper(III) Species/SUSCATCU3
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.identifier.idgrec
025863
dc.contributor.funder
dc.relation.FundingProgramme
dc.relation.ProjectAcronym
dc.identifier.eissn
1520-5126