Structural and mechanistic insights into s-block bimetallic catalysis : sodium magnesiate-catalyzed guanylation of amines

De Tullio, Marco and Hernán-Gómez, Alberto and Livingstone, Zoe and Clegg, William and Kennedy, Alan R. and Harrington, Ross W. and Antiñolo, Antonio and Martínez, Antonio and Carrillo-Hermosilla, Fernando and Hevia, Eva (2016) Structural and mechanistic insights into s-block bimetallic catalysis : sodium magnesiate-catalyzed guanylation of amines. Chemistry - A European Journal, 22 (49). pp. 17646-17656. ISSN 1521-3765 (https://doi.org/10.1002/chem.201602906)

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Abstract

To advance the catalytic applications of s-block mixed-metal complexes, sodium magnesiate [NaMg(CH2SiMe3)3] (1) is reported as an efficient precatalyst for the guanylation of a variety of anilines and secondary amines with carbodiimides. First examples of hydrophosphination of carbodiimides by using a Mg catalyst are also described. The catalytic ability of the mixed-metal system is much greater than that of its homometallic components [NaCH2SiMe3 ] and [Mg(CH2SiMe3)2]. Stoichiometric studies suggest that magnesiate amido and guanidinate complexes are intermediates in these catalytic routes. Reactivity and kinetic studies imply that these guanylation reactions occur via (tris)amide intermediates that react with carbodiiimides in insertion steps. The rate law for the guanylation of N,N'-diisopropylcarbodiimide with 4-tert-butylaniline catalyzed by 1 is first order with respect to [amine], [carbodiimide], and [catalyst], and the reaction shows a large kinetic isotopic effect, which is consistent with an amine-assisted rate-determining carbodiimide insertion transition state. Studies to assess the effect of sodium in these transformations denote a secondary role with little involvement in the catalytic cycle.

ORCID iDs

De Tullio, Marco ORCID logoORCID: https://orcid.org/0000-0003-4173-2462, Hernán-Gómez, Alberto ORCID logoORCID: https://orcid.org/0000-0001-8150-7249, Livingstone, Zoe, Clegg, William, Kennedy, Alan R. ORCID logoORCID: https://orcid.org/0000-0003-3652-6015, Harrington, Ross W., Antiñolo, Antonio, Martínez, Antonio, Carrillo-Hermosilla, Fernando and Hevia, Eva ORCID logoORCID: https://orcid.org/0000-0002-3998-7506;
  • Item type:Article
    ID code:59281
    Dates:
    Date
    Event
    5 December 2016
    Published
    27 October 2016
    Published Online
    27 June 2016
    Accepted
    Notes:This is the peer reviewed version of the following article: De Tullio, M., Hernán-Gómez, A., Livingstone, Z., Clegg, W., Kennedy, A. R., Harrington, R. W., ... Hevia, E. (2016). Structural and mechanistic insights into s-block bimetallic catalysis: sodium magnesiate-catalyzed guanylation of amines. Chemistry - A European Journal, 22(49), 17646-17656, which has been published in final form at https://dx.doi.org/10.1002/chem.201602906. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
    Subjects:Science > Chemistry
    Department:Faculty of Science > Pure and Applied Chemistry
    Depositing user: Pure Administrator
    Date deposited:05 Jan 2017 14:57
    Last modified:18 Nov 2024 20:14
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/59281
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