Water-Promoted Generation of a Diazairida Homobarrelene by C-C Coupling Between an Iridacyclic Alkylidene and Acetonitrile

María F Espada; Joaquín López-Serrano; Manuel L Poveda; Ernesto Carmona

doi:10.1002/anie.201503149

Water-Promoted Generation of a Diazairida Homobarrelene by C-C Coupling Between an Iridacyclic Alkylidene and Acetonitrile

Angew Chem Int Ed Engl. 2015 Jul 20;54(30):8751-5. doi: 10.1002/anie.201503149. Epub 2015 Jun 10.

Authors

María F Espada¹, Joaquín López-Serrano¹, Manuel L Poveda², Ernesto Carmona³

Affiliations

¹ Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain).
² Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain). mpoveda@iiq.csic.es.
³ Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Consejo Superior de Investigaciones Científicas (CSIC) and Universidad de Sevilla, Avda. Américo Vespucio, 49, 41092 Sevilla (Spain). guzman@us.es.

PMID: 26095956
DOI: 10.1002/anie.201503149

Abstract

The stable cationic iridacyclopentenylidene [Tp(Me2)Ir(=CHC(Me)=C(Me)CH2(NCMe)]PF6 (A; Tp(Me2)=hydrotris(3,5-dimethylpyrazolyl)borate) has been obtained by α-hydride abstraction from the iridacyclopent-2-ene [Tp(Me2)Ir(CH2C(Me)=C(Me)CH2)(NCMe)]. Complex A exhibits Brønsted-Lowry acidity at the Ir-CH2 and proximal (relative to Ir-CH2 ) methyl sites. The coordination of an extra molecule of acetonitrile to the iridium center initiates the reversible isomerization of the chelating carbon chain of A to the monodentate butadienyl ligand of complex [Tp(Me2)Ir(CH=C(Me)C(Me)=CH2)(NCMe)2]PF6, which is capable to engage in a water-promoted C-C coupling with the MeCN co-ligands. The product is an aesthetically appealing bicyclic structure that resembles the hydrocarbon barrelene.

Keywords: CC coupling; alkylidenes; iridium; water catalysis.