α-Dicationic Chelating Phosphines: Synthesis and Application to the Hydroarylation of Dienes.
A series of new P^P-chelating ligands constituted by a dicationic -[P(H2Im)2]+2unit (H2Im = 1,3-dimethyl-4,5-dihydroimidazol-2-ylidene) and a -PPh2group connected through structurally different backbones have been synthesized. Evaluation of their reactivity toward different metal centers provides evidence that the dicationic fragment, otherwise reluctant to coordinate metals, readily participates in the formation of chelates when embedded into such a scaffold. Moreover, it significantly enhances the Lewis acidity of the metals to which it coordinates. This property has been used to develop a Rh catalyst that efficiently triggers the hydroarylation of dienes with electron-rich aromatic molecules. Kinetic studies and deuterium-labeling experiments, as well as density functional theory calculations, were performed in order to rationalize these findings.
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen , Tammannstraße 2, 37077 Göttingen, Germany.
Lianghu
L
Gu
Department of Chemistry, University of Massachusetts Lowel , Lowell, Massachusetts 01854, United States.
Lawrence M
LM
Wolf
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen , Tammannstraße 2, 37077 Göttingen, Germany.
Adam
A
Zieliński
Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
Walter
0000-0001-6780-0350
W
Thiel
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen , Tammannstraße 2, 37077 Göttingen, Germany.
Manuel
0000-0002-5491-5682
M
Alcarazo