When Martin's Spirosilane Meets a N-Heterocyclic Carbene (NHC)

Martin’s spirosilane first synthetized in 1979[1], has attracted some interest[2] due to its high Lewis acidity, steric hindrance and the intrinsic ability of the silicon atom to become hypervalent[3]. In our study we were... [ view full abstract ]

Martin’s spirosilane first synthetized in 1979[1], has attracted some interest[2] due to its high Lewis acidity, steric hindrance and the intrinsic ability of the silicon atom to become hypervalent[3]. In our study we were particularly interested in the interactions between this spirosilane and different NHCs, known as stable species, with a tunable Lewis basicity and steric hindrance[4]. We started studying the interactions between the two partners that allowed us to obtain different adducts: the normal one with small carbenes (IMe, IMes), and the abnormal[5] one in presence of hindered carbenes (ItBu, IPr). This last result can be a hint of a Frustrated Lewis Pair behaviour for the activation of small molecules like H₂[6], CO₂[7] and formaldehyde[8]. We also investigated their potential use as ligands for metal catalysis.

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  c) H. Lenormand, J.-P. Goddard, L. Fensterbank, Org. Lett. 2013, 15, 748–751.

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[4] a) S. Díez-González, S. P. Nolan, Coord. Chem. Rev. 2007, 251, 874–883;  b) D. Enders, O. Niemeier, A. Henseler, Chem. Rev. 2007, 107, 5606–5655; c) W. A. Herrmann, Angew. Chem. Int. Ed. 2002, 41, 1290–1309.

[5] P. L. Arnold, S. Pearson, Coord. Chem. Rev. 2007, 251, 596–609

[6] D. W. Stephan, G. Erker, Angew. Chem. Int. Ed. 2010, 49, 46–76.

[7] C. M. Mömming, E. Otten, G. Kehr, R. Fröhlich, S. Grimme, D. W. Stephan, G. Erker, Angew. Chem. Int. Ed. 2009, 48, 6643–6646.

[8] G. Ghattas, C. Bizzarri, M. Hoelscher, J. Langanke, C. Gürtler, W. Leitner, M. A. Subhani, Chem. Commun. 2017