title: Bis(cyclopropenium)phosphines: Synthesis, Reactivity, and Applications.
abstract: A straightforward route for the preparation of a set of bis(cyclopropenium)-substituted phosphines is reported. Due to their dicationic nature, these ligands depict an excellent π-acceptor character. The effect of the ligand substituent pattern on the catalytic activity of the metal complexes thereof derived is also studied. Whereas sterically demanding biaryl groups directly attached to the phosphorus atom seem to facilitate elementary steps such as the product release from the catalyst, long chain dialkylamino groups on the cyclopropenium units maximize the catalysts solubility and, thus, allow the use of typical apolar solvents such as toluene. Importantly, all new ligands prepared can be easily handled in air. Finally, the impact of the newly prepared dicationic phosphines in hydroarylation reactions is demonstrated. In particular, their use in the synthesis of several naphtho[1,2-b]furanes and naturally occurring naphthalene derivatives such as Calanquinone C is reported.
authors.affiliation: Max-Planck-Institut für Kohlenforschung, Kaiser Wilhelm Platz 1, 45470, Mülheim an der Ruhr, Germany.
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Mehler
authors.affiliation: Max-Planck-Institut für Kohlenforschung, Kaiser Wilhelm Platz 1, 45470, Mülheim an der Ruhr, Germany.
authors.forename: Pawel
authors.initials: P
authors.lastname: Linowski
authors.affiliation: Max-Planck-Institut für Kohlenforschung, Kaiser Wilhelm Platz 1, 45470, Mülheim an der Ruhr, Germany.
authors.forename: Javier
authors.initials: J
authors.lastname: Carreras
authors.affiliation: Max-Planck-Institut für Kohlenforschung, Kaiser Wilhelm Platz 1, 45470, Mülheim an der Ruhr, Germany.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Zanardi
authors.affiliation: Georg-August-Universität Göttingen, Tammanstraße 2, 37077, Göttingen, Germany.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Dube
authors.affiliation: Georg-August-Universität Göttingen, Tammanstraße 2, 37077, Göttingen, Germany. Manuel.Alcarazo@chemie.uni-goettingen.de.
authors.forename: Manuel
authors.initials: M
authors.lastname: Alcarazo
keywords: cationic ligands; homogeneous catalysis; hydroarylation; ligand design; π-acid catalysis