14:25 - 14:55 I-1 - Advances in Organic and Inorganic Chemistry

Heterolytic Splitting of Dihydrogen with Copper Complexes - Replacing Complex Hydrides with H2

Johannes Teichert

Technische Universität Berlin, GER

One of the main challenges of contemporary method development for synthetic chemistry is the development of atom economic and sustainable transformations. 1 In this vein, catalytic hydrogenations are much desired reactions, as they serve to replace complex and waste-generating reducing agents such as borohydrides, aluminium hydrides or hydrosilanes. 2

We have developed several copper(I) complexes (mostly based on N-heterocyclic carbene ligands) that allow for heterolytic activation of H2 through the presence of an intermediately formed Cu–O-bond. These complexes can be employed in “classic” hydrogenation reactions such as stereo and chemoselective alkyne semihydrogenations. 3 However, one of the main features of these catalysts is the feat that they produce nucleophilic hydrides, which can be used in reductive coupling reactions 4 or the catalytic reduction of carboxyl derivatives such as esters and amides. 5 These processes generally require stoichiometric and waste-producing reducing agents, which can now be replaced by the more atom economic H2. In the abovementioned catalytic transformations, the copper complexes studied display a remarkable chemoselectivity, leaving alkenes – generally prime substrates for catalytic hydrogenations – intact.

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  1. For a review on green chemistry, see: a) P. Anastas, N. Eghbali, Chem. Soc. Rev., 2010, 39, 301. For reviews on atom economy and atom efficiency, see: b) B. M. Trost, Angew. Chem. Int. Ed., 1995, 34, 259; c) R. A. Sheldon, Chem. Soc. Rev., 2012, 41, 1437.

  2. a) The use of H2 as reagent has been put forward, see for example: R. Noyorii, Chem. Commun., 2005, 1807; b) D. J. C. Constable, P. J. Dunn, J. D. Hayler, G. R. Humphrey, J. J. L. Leazer, R. J. Linderman, K. Lorenz, J. Manley, B. A. Pearlman, A. Wells, A. Zaks, T. Y. Zhang, Green Chem., 2007, 9, 411.

  3. See, for example: a) F. Pape, N. O. Thiel, J. F. Teichert, Chem. Eur. J. 2015, 21, 15934; b) N. O. Thiel, J. F. Teichert, Org. Biomol. Chem. 2016, 14, 10660; c) B. M. Zimmermann, S. C. K. Kobosil, J. F. Teichert, Chem. Commun. 2019, DOI: 10.1039/C8CC09853K.

  4. F. Pape, L. T. Brechmann, J. F. Teichert, Chem. Eur. J. 2019, 25, 985.

  5. B. M. Zimmermann, T. Kaicharla, J. F. Teichert, submitted.