Chiral oxazolidines acting as transient hydroxyalkyl-functionalized N-heterocyclic carbenes: an efficient route to air stable copper and gold complexes for asymmetric catalysis

Delphine Pichon-Barré; Ziyun Zhang; Aël Cador; Thomas Vives; Thierry Roisnel; Olivier Baslé; Lucie Jarrige; Luigi Cavallo; Laura Falivene; Marc Mauduit

doi:10.1039/d2sc02908a

Chiral oxazolidines acting as transient hydroxyalkyl-functionalized N-heterocyclic carbenes: an efficient route to air stable copper and gold complexes for asymmetric catalysis

Delphine Pichon-Barré, Ziyun Zhang, Aël Cador, Thomas Vives, Thierry Roisnel, Olivier Baslé, Lucie Jarrige, Luigi Cavallo, Laura Falivene, Marc Mauduit

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Abstract

Optically pure oxazolidines were synthesized in nearly quantitative yields from chiral hydroxyalkyl-functionalized imidazolinium salts. Acting as transient chiral diamino N-heterocyclic carbenes (NHCs), these oxazolidines allowed the efficient formation of well-defined copper(I) and gold(I) hydroxyalkyl-NHC complexes, which could be isolated, for the first time, as air stable complexes after silica gel chromatography. Interestingly, X-ray analysis of gold complexes revealed that the hydroxyl-function is not chelated to the metal. Computational studies suggested that both cyclisation to produce oxazolidine and O–H bond elimination to form the transient carbene (prior to coordination) occur through a concerted mechanism. The novel chiral copper-catalysts, as well as oxazolidines alone (copper free), demonstrated excellent performances in asymmetric conjugate addition and allylic alkylation with high regio- and enantio-selectivities (up to 99% ee).

Original language	English (US)
Journal	Chemical Science
DOIs	https://doi.org/10.1039/d2sc02908a
State	Published - Jul 11 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-09-14
Acknowledgements: We are grateful to the CNRS, the Ecole Nationale Supérieure de Chimie de Rennes. Umicore AG & Co is acknowledged for a generous gift of gold complexes. This work was supported by the Agence Nationale de la Recherche (ANR-16-CE07-0019 “Hel-NHC” grant to D. P.-B.). L. J. thanks Rennes Metropole for supporting this work through the AIS grant for young researchers. L. C., L. F. and Z. Z. thank the King Abdullah University of Science and Technology (KAUST) for supporting this work. For computer time, this research used the resources of the KAUST Super-computing Laboratory (KSL) at KAUST. We are grateful to Philippe Jéhan and the CRMPO core facility for HMRS of Au- and Cu-complexes.

ASJC Scopus subject areas

General Chemistry

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https://repository.kaust.edu.sa/bitstream/10754/679653/1/d2sc02908a.pdf

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@article{52644ad725624750a2bea24b5b9b9587,

title = "Chiral oxazolidines acting as transient hydroxyalkyl-functionalized N-heterocyclic carbenes: an efficient route to air stable copper and gold complexes for asymmetric catalysis",

abstract = "Optically pure oxazolidines were synthesized in nearly quantitative yields from chiral hydroxyalkyl-functionalized imidazolinium salts. Acting as transient chiral diamino N-heterocyclic carbenes (NHCs), these oxazolidines allowed the efficient formation of well-defined copper(I) and gold(I) hydroxyalkyl-NHC complexes, which could be isolated, for the first time, as air stable complexes after silica gel chromatography. Interestingly, X-ray analysis of gold complexes revealed that the hydroxyl-function is not chelated to the metal. Computational studies suggested that both cyclisation to produce oxazolidine and O–H bond elimination to form the transient carbene (prior to coordination) occur through a concerted mechanism. The novel chiral copper-catalysts, as well as oxazolidines alone (copper free), demonstrated excellent performances in asymmetric conjugate addition and allylic alkylation with high regio- and enantio-selectivities (up to 99% ee).",

author = "Delphine Pichon-Barr{\'e} and Ziyun Zhang and A{\"e}l Cador and Thomas Vives and Thierry Roisnel and Olivier Basl{\'e} and Lucie Jarrige and Luigi Cavallo and Laura Falivene and Marc Mauduit",

note = "KAUST Repository Item: Exported on 2022-09-14 Acknowledgements: We are grateful to the CNRS, the Ecole Nationale Sup{\'e}rieure de Chimie de Rennes. Umicore AG & Co is acknowledged for a generous gift of gold complexes. This work was supported by the Agence Nationale de la Recherche (ANR-16-CE07-0019 “Hel-NHC” grant to D. P.-B.). L. J. thanks Rennes Metropole for supporting this work through the AIS grant for young researchers. L. C., L. F. and Z. Z. thank the King Abdullah University of Science and Technology (KAUST) for supporting this work. For computer time, this research used the resources of the KAUST Super-computing Laboratory (KSL) at KAUST. We are grateful to Philippe J{\'e}han and the CRMPO core facility for HMRS of Au- and Cu-complexes.",

year = "2022",

month = jul,

day = "11",

doi = "10.1039/d2sc02908a",

language = "English (US)",

journal = "Chemical Science",

issn = "2041-6520",

publisher = "Royal Society of Chemistry",

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T1 - Chiral oxazolidines acting as transient hydroxyalkyl-functionalized N-heterocyclic carbenes: an efficient route to air stable copper and gold complexes for asymmetric catalysis

AU - Pichon-Barré, Delphine

AU - Zhang, Ziyun

AU - Cador, Aël

AU - Vives, Thomas

AU - Roisnel, Thierry

AU - Baslé, Olivier

AU - Jarrige, Lucie

AU - Cavallo, Luigi

AU - Falivene, Laura

AU - Mauduit, Marc

N1 - KAUST Repository Item: Exported on 2022-09-14 Acknowledgements: We are grateful to the CNRS, the Ecole Nationale Supérieure de Chimie de Rennes. Umicore AG & Co is acknowledged for a generous gift of gold complexes. This work was supported by the Agence Nationale de la Recherche (ANR-16-CE07-0019 “Hel-NHC” grant to D. P.-B.). L. J. thanks Rennes Metropole for supporting this work through the AIS grant for young researchers. L. C., L. F. and Z. Z. thank the King Abdullah University of Science and Technology (KAUST) for supporting this work. For computer time, this research used the resources of the KAUST Super-computing Laboratory (KSL) at KAUST. We are grateful to Philippe Jéhan and the CRMPO core facility for HMRS of Au- and Cu-complexes.

PY - 2022/7/11

Y1 - 2022/7/11

N2 - Optically pure oxazolidines were synthesized in nearly quantitative yields from chiral hydroxyalkyl-functionalized imidazolinium salts. Acting as transient chiral diamino N-heterocyclic carbenes (NHCs), these oxazolidines allowed the efficient formation of well-defined copper(I) and gold(I) hydroxyalkyl-NHC complexes, which could be isolated, for the first time, as air stable complexes after silica gel chromatography. Interestingly, X-ray analysis of gold complexes revealed that the hydroxyl-function is not chelated to the metal. Computational studies suggested that both cyclisation to produce oxazolidine and O–H bond elimination to form the transient carbene (prior to coordination) occur through a concerted mechanism. The novel chiral copper-catalysts, as well as oxazolidines alone (copper free), demonstrated excellent performances in asymmetric conjugate addition and allylic alkylation with high regio- and enantio-selectivities (up to 99% ee).

AB - Optically pure oxazolidines were synthesized in nearly quantitative yields from chiral hydroxyalkyl-functionalized imidazolinium salts. Acting as transient chiral diamino N-heterocyclic carbenes (NHCs), these oxazolidines allowed the efficient formation of well-defined copper(I) and gold(I) hydroxyalkyl-NHC complexes, which could be isolated, for the first time, as air stable complexes after silica gel chromatography. Interestingly, X-ray analysis of gold complexes revealed that the hydroxyl-function is not chelated to the metal. Computational studies suggested that both cyclisation to produce oxazolidine and O–H bond elimination to form the transient carbene (prior to coordination) occur through a concerted mechanism. The novel chiral copper-catalysts, as well as oxazolidines alone (copper free), demonstrated excellent performances in asymmetric conjugate addition and allylic alkylation with high regio- and enantio-selectivities (up to 99% ee).

UR - http://hdl.handle.net/10754/679653

UR - http://xlink.rsc.org/?DOI=D2SC02908A

U2 - 10.1039/d2sc02908a

DO - 10.1039/d2sc02908a

M3 - Article

C2 - 35975143

SN - 2041-6520

JO - Chemical Science

JF - Chemical Science

ER -

Chiral oxazolidines acting as transient hydroxyalkyl-functionalized N-heterocyclic carbenes: an efficient route to air stable copper and gold complexes for asymmetric catalysis

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