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A Metal–Ligand Cooperative Pathway for Intermolecular Oxa‐Michael Additions to Unsaturated Nitriles |
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| Authors: | Sébastien Perdriau Douwe S. Zijlstra Prof. Dr. Hero J. Heeres Prof. Dr. Johannes G. de Vries Dr. Edwin Otten |
| Affiliation: | 1. Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen (The Netherlands);2. Department of Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen (The Netherlands);3. Leibniz‐Institut für Katalyse an der Universit?t Rostock, Albert‐Einstein‐Strasse 29a, 18059 Rostock (Germany) |
| Abstract: | An unprecedented catalytic pathway for oxa‐Michael addition reactions of alcohols to unsaturated nitriles has been revealed using a PNN pincer ruthenium catalyst with a dearomatized pyridine backbone. The isolation of a catalytically competent Ru–dieneamido complex from the reaction between the Ru catalyst and pentenenitrile in combination with DFT calculations supports a mechanism in which activation of the nitrile through metal–ligand cooperativity is a key step. The nitrile‐derived Ru‐N moiety is sufficiently Brønsted basic to activate the alcohol and initiate conjugate addition of the alkoxide to the α,β‐unsaturated fragment. This reaction proceeds in a concerted manner and involves a six‐membered transition state. These features allow the reaction to proceed at ambient temperature in the absence of external base. |
| Keywords: | homogeneous catalysis Michael addition non‐innocent ligands pincer ligands ruthenium |