title: Gold-Catalyzed Intermolecular Formal Insertion of Aryldiazo Esters into Cp-H Bonds of Iron and Ruthenium Metallocenes.
abstract: The reaction of ferrocene and ruthenocene with aryldiazo acetates in the presence of gold catalysts produced new functionalized metallocenes resulting from a C-H bond functionalization process. This process is believed to proceed through initial decomposition of the diazo component and formation of an electrophilic gold-carbene intermediate, which is subsequently involved in an electrophilic aromatic substitution. The gold-catalyzed functionalization of ruthenocene exhibited a broad scope and a notable functional-group tolerance. Interestingly, the functionalized ferrocene derivatives were found to react with molecular oxygen to yield α-aryl-α-ferrocenyl-α-hydroxyacetates. Adsorption on silica gel was found to be essential for this dioxygen activation/C(sp3)-H bond functionalization sequence. The methodologies reported herein provide a simple and efficient approach to functionalized metallocene derivatives that are difficult to access through conventional organic functional group transformations.
authors.affiliation: Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica "Enrique Moles", Universidad de Oviedo, Julián Clavería 8, 33006-, Oviedo, Spain.
authors.forename: Enol
authors.initials: E
authors.lastname: López
authors.affiliation: Departamento de Química FísicayAnalítica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Oviedo, Julián Clavería 8, 33006-, Oviedo, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Borge
authors.affiliation: Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica "Enrique Moles", Universidad de Oviedo, Julián Clavería 8, 33006-, Oviedo, Spain.
authors.forename: Luis A
authors.initials: LA
authors.lastname: López
keywords: C−H activation; diazo compounds; gold; metallocenes; oxidation