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A Metal–Ligand Cooperative Pathway for Intermolecular Oxa‐Michael Additions to Unsaturated Nitriles
Author(s) -
Perdriau Sébastien,
Zijlstra Douwe S.,
Heeres Hero J.,
de Vries Johannes G.,
Otten Edwin
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201412110
Subject(s) - chemistry , nitrile , ruthenium , catalysis , moiety , ligand (biochemistry) , alkoxide , pincer movement , pyridine , homogeneous catalysis , photochemistry , combinatorial chemistry , medicinal chemistry , stereochemistry , organic chemistry , biochemistry , receptor
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.