title: Well-Defined Dinuclear Gold Complexes for Preorganization-Induced Selective Dual Gold Catalysis.
abstract: The synthesis, reactivity, and potential of well-defined dinuclear gold complexes as precursors for dual gold catalysis are explored. Using the preorganizing abilities of the ditopic PN(H) P(iPr) (L(H) ) ligand, dinuclear Au(I) -Au(I) complex 1 and mixed-valent Au(I) -Au(III) complex 2 provide access to structurally characterized chlorido-bridged cationic species 3 and 4 upon halide abstraction. For 2, this transformation involves unprecedented two-electron oxidation of the redox-active ligand, generating a highly rigidified environment for the Au2 core. Facile reaction with phenylacetylene affords the σ,π-activated phenylacetylide complex 5. When applied in the dual gold heterocycloaddition of a urea-functionalized alkyne, well-defined precatalyst 3 provides high regioselectivities for the anti-Markovnikov product, even at low catalyst loadings, and outperforms common mononuclear Au(I) systems. This proof-of-concept demonstrates the benefit of preorganization of two gold centers to enforce selective non-classical σ,π-activation with bifunctional substrates.
authors.affiliation: Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Vincent
authors.initials: V
authors.lastname: Vreeken
authors.affiliation: Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Daniël L J
authors.initials: DL
authors.lastname: Broere
authors.affiliation: Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Anne C H
authors.initials: AC
authors.lastname: Jans
authors.affiliation: Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Marianne
authors.initials: M
authors.lastname: Lankelma
authors.affiliation: Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Joost N H
authors.initials: JN
authors.lastname: Reek
authors.affiliation: Small Molecule X-ray Crystallography Facility, Department of Chemistry, John Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA.
authors.forename: Maxime A
authors.initials: MA
authors.lastname: Siegler
authors.affiliation: Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands. j.i.vandervlugt@uva.nl.
authors.forename: Jarl Ivar
authors.initials: JI
authors.lastname: van der Vlugt
keywords: bridging acetylide; dinuclear gold complexes; dual gold catalysis; redox-active ligand; σ,π-activation