Alkali-metal-mediated magnesiations of an N-heterocyclic carbene: normal, abnormal and "paranormal" reactivity in a single tritopic molecule

Antonio J. Martínez-Martínez, M. Ángeles Fuentes, Alberto Hernán-Gõmez, Eva Hevia, Alan R. Kennedy, Robert E. Mulvey, Charles T. O'Hara

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Herein the sodium alkylmagnesium amide [Na4Mg2(TMP)6(nBu)2] (TMP=2,2,6,6-tetramethylpiperidide), a template base as its deprotonating action is dictated primarily by its 12 atom ring structure, is studied with the common N-heterocyclic carbene (NHC) IPr [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]. Remarkably, magnesiation of IPr occurs at the para-position of an aryl substituent, sodiation occurs at the abnormal C4 position, and a dative bond occurs between normal C2 and sodium, all within a 20 atom ring structure accommodating two IPr2-. Studies with different K/Mg and Na/Mg bimetallic bases led to two other magnesiated NHC structures containing two or three IPr- monoanions bound to Mg through abnormal C4 sites. Synergistic in that magnesiation can only work through alkali-metal mediation, these reactions add magnesium to the small cartel of metals capable of directly metalating a NHC.

LanguageEnglish
Pages14075-14079
Number of pages5
JournalAngewandte Chemie International Edition
Volume54
Issue number47
Early online date29 Sep 2015
DOIs
Publication statusPublished - 16 Nov 2015

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Alkali Metals
Alkali metals
Thymidine Monophosphate
Sodium
Atoms
Molecules
Amides
Magnesium
Metals
carbene

Keywords

  • alkali metals
  • carbenes
  • crown compounds
  • magnesium
  • metalation

Cite this

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title = "Alkali-metal-mediated magnesiations of an N-heterocyclic carbene: normal, abnormal and {"}paranormal{"} reactivity in a single tritopic molecule",
abstract = "Herein the sodium alkylmagnesium amide [Na4Mg2(TMP)6(nBu)2] (TMP=2,2,6,6-tetramethylpiperidide), a template base as its deprotonating action is dictated primarily by its 12 atom ring structure, is studied with the common N-heterocyclic carbene (NHC) IPr [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]. Remarkably, magnesiation of IPr occurs at the para-position of an aryl substituent, sodiation occurs at the abnormal C4 position, and a dative bond occurs between normal C2 and sodium, all within a 20 atom ring structure accommodating two IPr2-. Studies with different K/Mg and Na/Mg bimetallic bases led to two other magnesiated NHC structures containing two or three IPr- monoanions bound to Mg through abnormal C4 sites. Synergistic in that magnesiation can only work through alkali-metal mediation, these reactions add magnesium to the small cartel of metals capable of directly metalating a NHC.",
keywords = "alkali metals, carbenes, crown compounds, magnesium, metalation",
author = "Mart{\'i}nez-Mart{\'i}nez, {Antonio J.} and Fuentes, {M. {\'A}ngeles} and Alberto Hern{\'a}n-G{\~o}mez and Eva Hevia and Kennedy, {Alan R.} and Mulvey, {Robert E.} and O'Hara, {Charles T.}",
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Alkali-metal-mediated magnesiations of an N-heterocyclic carbene : normal, abnormal and "paranormal" reactivity in a single tritopic molecule. / Martínez-Martínez, Antonio J.; Fuentes, M. Ángeles; Hernán-Gõmez, Alberto; Hevia, Eva; Kennedy, Alan R.; Mulvey, Robert E.; O'Hara, Charles T.

In: Angewandte Chemie International Edition, Vol. 54, No. 47, 16.11.2015, p. 14075-14079.

Research output: Contribution to journalArticle

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T1 - Alkali-metal-mediated magnesiations of an N-heterocyclic carbene

T2 - Angewandte Chemie International Edition

AU - Martínez-Martínez, Antonio J.

AU - Fuentes, M. Ángeles

AU - Hernán-Gõmez, Alberto

AU - Hevia, Eva

AU - Kennedy, Alan R.

AU - Mulvey, Robert E.

AU - O'Hara, Charles T.

N1 - This is the peer reviewed version of the following article: Martínez-Martínez, A. J., Fuentes, M. Á., Hernán-Gómez, A., Hevia, E., Kennedy, A. R., Mulvey, R. E. and O'Hara, C. T. (2015), Alkali-Metal-Mediated Magnesiations of an N-Heterocyclic Carbene: Normal, Abnormal, and “Paranormal” Reactivity in a Single Tritopic Molecule. Angew. Chem. Int. Ed., 54: 14075–14079, which has been published in final form at http://dx.doi.org/doi: 10.1002/anie.201507586. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

PY - 2015/11/16

Y1 - 2015/11/16

N2 - Herein the sodium alkylmagnesium amide [Na4Mg2(TMP)6(nBu)2] (TMP=2,2,6,6-tetramethylpiperidide), a template base as its deprotonating action is dictated primarily by its 12 atom ring structure, is studied with the common N-heterocyclic carbene (NHC) IPr [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]. Remarkably, magnesiation of IPr occurs at the para-position of an aryl substituent, sodiation occurs at the abnormal C4 position, and a dative bond occurs between normal C2 and sodium, all within a 20 atom ring structure accommodating two IPr2-. Studies with different K/Mg and Na/Mg bimetallic bases led to two other magnesiated NHC structures containing two or three IPr- monoanions bound to Mg through abnormal C4 sites. Synergistic in that magnesiation can only work through alkali-metal mediation, these reactions add magnesium to the small cartel of metals capable of directly metalating a NHC.

AB - Herein the sodium alkylmagnesium amide [Na4Mg2(TMP)6(nBu)2] (TMP=2,2,6,6-tetramethylpiperidide), a template base as its deprotonating action is dictated primarily by its 12 atom ring structure, is studied with the common N-heterocyclic carbene (NHC) IPr [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]. Remarkably, magnesiation of IPr occurs at the para-position of an aryl substituent, sodiation occurs at the abnormal C4 position, and a dative bond occurs between normal C2 and sodium, all within a 20 atom ring structure accommodating two IPr2-. Studies with different K/Mg and Na/Mg bimetallic bases led to two other magnesiated NHC structures containing two or three IPr- monoanions bound to Mg through abnormal C4 sites. Synergistic in that magnesiation can only work through alkali-metal mediation, these reactions add magnesium to the small cartel of metals capable of directly metalating a NHC.

KW - alkali metals

KW - carbenes

KW - crown compounds

KW - magnesium

KW - metalation

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DO - 10.1002/anie.201507586

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JO - Angewandte Chemie International Edition

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