Well‐Defined Dinuclear Gold Complexes for Preorganization‐Induced Selective Dual Gold Catalysis |
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| Authors: | Vincent Vreeken Dr Daniël L J Broere Anne C H Jans Marianne Lankelma Prof?Dr Joost N H Reek Dr Maxime A Siegler Dr Jarl Ivar van?der?Vlugt |
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| Institution: | 1. Homogeneous, Bioinspired and Supramolecular Catalysis, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands;2. Small Molecule X-ray Crystallography Facility, Department of Chemistry, John Hopkins University, Baltimore, MD, USA |
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| 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 PNHPiPr ( LH ) ligand, dinuclear AuI–AuI complex 1 and mixed‐valent AuI–AuIII 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 AuI 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. |
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| Keywords: | σ π -activation bridging acetylide dinuclear gold complexes dual gold catalysis redox-active ligand |
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