10.1002/anie.201901090
Angewandte Chemie International Edition
COMMUNICATION
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complex (see Supporting Information). With an efficient set of
reaction conditions in hand, and considering the much faster
conversions with gold complex 5Me, we further challenged the
efficiency of the catalyst by conducting the hydroarylation/
cyclization reaction on a 1-gram scale (3 mmol) and in the
presence of 0.25 mol% of gold catalyst (see Supporting
Information). Remarkably, the heterocycle 9c was isolated in 87%
yield, which corresponds to a decrease in catalyst loading of more
than 3 orders of magnitude from this work, and 10 orders of
magnitude from previous studies.[25]
In conclusion, we reported the straightforward and efficient
synthesis of new NHC ligands based on an imidazo[1,5-a]pyridin-
3-ylidene (IPy) scaffold functionalized by a flanking barbituric
heterocycle and their use as tunable and efficient NHC ligands for
original gold-catalyzed reactions. The efficiency of the related
Au(I) complexes was evaluated in C-N, C-O and C-C bonds
formation, according to hydroelementation reactions as well as
domino processes, with high to excellent TONs and TOFs under
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the supplementary crystallographic data for this paper. These data can
be obtained free of charge from The Cambridge Crystallographic Data
Centre.
Acknowledgements
This work was supported by the Agence Nationale de Recherche
(ANR-16-CE07-0006), the Centre National de la Recherche
Scientifique (CNRS) and the University Côte d’Azur. Y.T. and I.B.
are grateful to ANR for PhD grants.
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Keywords: N-heterocyclic carbene • gold • organometallic
complexes • catalysis • atom-economical reactions
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