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

doi:10.1002/anie.201507586

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

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

34 Citations (Scopus)

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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 IPr^2-. 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.

Original language	English
Pages (from-to)	14075-14079
Number of pages	5
Journal	Angewandte Chemie International Edition
Volume	54
Issue number	47
Early online date	29 Sept 2015
DOIs	https://doi.org/10.1002/anie.201507586
Publication status	Published - 16 Nov 2015

Keywords

alkali metals
carbenes
crown compounds
magnesium
metalation

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10.1002/anie.201507586

Martinez-Martinez-etal-ACIE-2015-Alkali-metal-mediated-magnesiations-of-an-NHCAccepted author manuscript, 1.33 MB

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Martínez-Martínez, A. J., Fuentes, M. Á., Hernán-Gõmez, A., Hevia, E., Kennedy, A. R., Mulvey, R. E., & O'Hara, C. T. (2015). Alkali-metal-mediated magnesiations of an N-heterocyclic carbene: normal, abnormal and "paranormal" reactivity in a single tritopic molecule. Angewandte Chemie International Edition, 54(47), 14075-14079. https://doi.org/10.1002/anie.201507586

@article{8cc3770c6373405fbc95fed4e421ad12,

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.}",

note = "This is the peer reviewed version of the following article: Mart{\'i}nez-Mart{\'i}nez, A. J., Fuentes, M. {\'A}., Hern{\'a}n-G{\'o}mez, 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.",

year = "2015",

month = nov,

day = "16",

doi = "10.1002/anie.201507586",

language = "English",

volume = "54",

pages = "14075--14079",

journal = "Angewandte Chemie International Edition",

issn = "1433-7851",

number = "47",

}

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

Research output: Contribution to journal › Article › peer-review

TY - JOUR

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

T2 - normal, abnormal and "paranormal" reactivity in a single tritopic molecule

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

UR - http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1521-3773

U2 - 10.1002/anie.201507586

DO - 10.1002/anie.201507586

M3 - Article

AN - SCOPUS:84954438503

SN - 1433-7851

VL - 54

SP - 14075

EP - 14079

JO - Angewandte Chemie International Edition

JF - Angewandte Chemie International Edition

IS - 47

ER -

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

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Robert Mulvey

Lithium Cuprates to Copper Lithiates: A New Dawn in Metal Catalysed Chemistry

A co-operative bimetallic approach for the transformation of lithiation

Chiral Concepts in s-Block Metal Amide Chemistry

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

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Lithium Cuprates to Copper Lithiates: A New Dawn in Metal Catalysed Chemistry

A co-operative bimetallic approach for the transformation of lithiation

Chiral Concepts in s-Block Metal Amide Chemistry

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