Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies

The direct [2 + 2]-photocycloaddition of (Z)-2-phenyl-4-aryliden-5(4H)-oxazolones 1 to give 1,3-diaminotruxillic cyclobutane derivatives 2 in very good yields (75-100%) is reported. The reaction takes place by irradiation of CHCl solutions of 1 with blue light (465 nm) provided by light-emitting dio...

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Autores: García-Montero, Ángel, Rodríguez-García, Antonio M., Juan, Alberto, Velders, Aldrik H., Denisi, Antonio, Jiménez-Osés, Gonzalo, Gómez-Bengoa, Enrique, Cativiela, Carlos, Gómez, M. Victoria, Urriolabeitia, Esteban P.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2017
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/164903
Acceso en línea:http://hdl.handle.net/10261/164903
Access Level:acceso abierto
Palabra clave:Photochemistry
[2 + 2]-Photocycloaddition
Truxillic acids
Oxazolones
In-line NMR
Flow chemistry
Diradical species
DFT calculations
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spelling Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studiesGarcía-Montero, ÁngelRodríguez-García, Antonio M.Juan, AlbertoVelders, Aldrik H.Denisi, AntonioJiménez-Osés, GonzaloGómez-Bengoa, EnriqueCativiela, CarlosGómez, M. VictoriaUrriolabeitia, Esteban P.Photochemistry[2 + 2]-PhotocycloadditionTruxillic acidsOxazolonesIn-line NMRFlow chemistryDiradical speciesDFT calculationsThe direct [2 + 2]-photocycloaddition of (Z)-2-phenyl-4-aryliden-5(4H)-oxazolones 1 to give 1,3-diaminotruxillic cyclobutane derivatives 2 in very good yields (75-100%) is reported. The reaction takes place by irradiation of CHCl solutions of 1 with blue light (465 nm) provided by light-emitting diode (LED) lamps of low power (around 1 W) for 72 h. Four isomers of the 1,3-diaminotruxillic cyclobutanes 2 were obtained; all of them fully characterized by a combination of nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction analysis. The reaction shows a certain selectivity, since one of the isomers (the epsilon) is obtained preferentially, and works for electron-releasing and electron-withdrawing substituents at the arylidene ring. A novel setup is presented for the in-line monitoring of the continuous flow photoassisted synthesis of the cyclobutane derivatives 2 by NMR spectroscopy, with the microreactor dramatically reducing reaction times to only 30 min with clear product distribution of up to four isomers. The mechanism of this [2 + 2]-photocycloaddition has been calculated by density functional theory (DFT) methods, explaining all experimental findings. The reaction takes place through a stepwise formation of two new C-C bonds through a transient diradical singlet intermediate. The isomeric distribution of the final products is not due to equilibration processes but instead reflects the kinetic preference during the rate limiting C-C bond formation step.C. C. and E. P. U. thank Ministerio de Economía, Industria y Competitividad (Spain, Project CTQ2013-40855R) and Gobierno de Aragón - Fondo Social Europeo (Spain, groups E-40 and E-97) for financial support. C. C. and E. P. U. also would like to acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. E. P. U. and E. G. B. thank COST program under CA15106 (CHAOS) grant. M. V. G. acknowledges Spanish Ministry of Economy, Industry and Competitivity (MINECO CTQ2014-54987-P) for financial support and for participation in the Ramón y Cajal program.Peer ReviewedAmerican Chemical SocietyMinisterio de Economía, Industria y Competitividad (España)European CommissionUniversidad de ZaragozaGobierno de AragónConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2018201820172018info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/164903reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/H2020/658982info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CTQ2014-54987-Pinfo:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CTQ2013-40855-Rhttps://doi.org/10.1021/acssuschemeng.7b02140Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1649032026-05-22T06:33:51Z
dc.title.none.fl_str_mv Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
title Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
spellingShingle Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
García-Montero, Ángel
Photochemistry
[2 + 2]-Photocycloaddition
Truxillic acids
Oxazolones
In-line NMR
Flow chemistry
Diradical species
DFT calculations
title_short Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
title_full Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
title_fullStr Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
title_full_unstemmed Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
title_sort Metal-free [2 + 2]-photocycloaddition of (Z)-4-aryliden-5(4H)-oxazolones as straightforward synthesis of 1,3-diaminotruxillic acid precursors: Synthetic scope and mechanistic studies
dc.creator.none.fl_str_mv García-Montero, Ángel
Rodríguez-García, Antonio M.
Juan, Alberto
Velders, Aldrik H.
Denisi, Antonio
Jiménez-Osés, Gonzalo
Gómez-Bengoa, Enrique
Cativiela, Carlos
Gómez, M. Victoria
Urriolabeitia, Esteban P.
author García-Montero, Ángel
author_facet García-Montero, Ángel
Rodríguez-García, Antonio M.
Juan, Alberto
Velders, Aldrik H.
Denisi, Antonio
Jiménez-Osés, Gonzalo
Gómez-Bengoa, Enrique
Cativiela, Carlos
Gómez, M. Victoria
Urriolabeitia, Esteban P.
author_role author
author2 Rodríguez-García, Antonio M.
Juan, Alberto
Velders, Aldrik H.
Denisi, Antonio
Jiménez-Osés, Gonzalo
Gómez-Bengoa, Enrique
Cativiela, Carlos
Gómez, M. Victoria
Urriolabeitia, Esteban P.
author2_role author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Ministerio de Economía, Industria y Competitividad (España)
European Commission
Universidad de Zaragoza
Gobierno de Aragón
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Photochemistry
[2 + 2]-Photocycloaddition
Truxillic acids
Oxazolones
In-line NMR
Flow chemistry
Diradical species
DFT calculations
topic Photochemistry
[2 + 2]-Photocycloaddition
Truxillic acids
Oxazolones
In-line NMR
Flow chemistry
Diradical species
DFT calculations
description The direct [2 + 2]-photocycloaddition of (Z)-2-phenyl-4-aryliden-5(4H)-oxazolones 1 to give 1,3-diaminotruxillic cyclobutane derivatives 2 in very good yields (75-100%) is reported. The reaction takes place by irradiation of CHCl solutions of 1 with blue light (465 nm) provided by light-emitting diode (LED) lamps of low power (around 1 W) for 72 h. Four isomers of the 1,3-diaminotruxillic cyclobutanes 2 were obtained; all of them fully characterized by a combination of nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction analysis. The reaction shows a certain selectivity, since one of the isomers (the epsilon) is obtained preferentially, and works for electron-releasing and electron-withdrawing substituents at the arylidene ring. A novel setup is presented for the in-line monitoring of the continuous flow photoassisted synthesis of the cyclobutane derivatives 2 by NMR spectroscopy, with the microreactor dramatically reducing reaction times to only 30 min with clear product distribution of up to four isomers. The mechanism of this [2 + 2]-photocycloaddition has been calculated by density functional theory (DFT) methods, explaining all experimental findings. The reaction takes place through a stepwise formation of two new C-C bonds through a transient diradical singlet intermediate. The isomeric distribution of the final products is not due to equilibration processes but instead reflects the kinetic preference during the rate limiting C-C bond formation step.
publishDate 2017
dc.date.none.fl_str_mv 2017
2018
2018
2018
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Postprint
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/164903
url http://hdl.handle.net/10261/164903
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
#PLACEHOLDER_PARENT_METADATA_VALUE#
#PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/H2020/658982
info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CTQ2014-54987-P
info:eu-repo/grantAgreement/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/CTQ2013-40855-R
https://doi.org/10.1021/acssuschemeng.7b02140
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv American Chemical Society
publisher.none.fl_str_mv American Chemical Society
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
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