title: Template Catalysis by Metal-Ligand Cooperation. C-C Bond Formation via Conjugate Addition of Non-activated Nitriles under Mild, Base-free Conditions Catalyzed by a Manganese Pincer Complex.
abstract: The first example of a catalytic Michael addition reaction of non-activated aliphatic nitriles to α,β-unsaturated carbonyl compounds under mild, neutral conditions is reported. A new de-aromatized pyridine-based PNP pincer complex of the Earth-abundant, first-row transition metal manganese serves as the catalyst. The reaction tolerates a variety of nitriles and Michael acceptors with different steric features and acceptor strengths. Mechanistic investigations including temperature-dependent NMR spectroscopy and DFT calculations reveal that the cooperative activation of alkyl nitriles, which leads to the generation of metalated nitrile nucleophile species (α-cyano carbanion analogues), is a key step of the mechanism. The metal center is not directly involved in the catalytic bond formation but rather serves, cooperatively with the ligand, as a template for the substrate activation. This approach of "template catalysis" expands the scope of potential donors for conjugate addition reactions.
authors.forename: Alexander
authors.initials: A
authors.lastname: Nerush
authors.affiliation: Institut für Anorganische Chemie und Kristallographie, Universität Bremen , Leobener Straße, 28359 Bremen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Vogt
authors.forename: Urs
authors.initials: U
authors.lastname: Gellrich
authors.forename: Gregory
authors.initials: G
authors.lastname: Leitus
authors.forename: Yehoshoa
authors.initials: Y
authors.lastname: Ben-David
authors.forename: David
authors.initials: D
authors.lastname: Milstein