Highly efficient nickel-catalyzed 2-methyl-3-butenenitrile isomerization

• Verfasst von: Tauchert, Michael E. [VerfasserIn]
• Verfasst von: Warth, Daniel C. M. [VerfasserIn]
• Verfasst von: Braun, Sebastian M. [VerfasserIn]
• Verfasst von: Pundt-Gruber, Irene [VerfasserIn]
• Verfasst von: Ziesak, Alexandra Sabrina [VerfasserIn]
• Verfasst von: Rominger, Frank [VerfasserIn]
• Verfasst von: Hofmann, Peter [VerfasserIn]
• Titel: Highly efficient nickel-catalyzed 2-methyl-3-butenenitrile isomerization
• Titelzusatz: applications and mechanistic studies employing the TTP ligand family
• Verf.angabe: Michael E. Tauchert, Daniel C.M. Warth, Sebastian M. Braun, Irene Gruber, Alexandra Ziesak, Frank Rominger, and Peter Hofmann
• E-Jahr: 2011
• Jahr: 21 April 2011
• Umfang: 20 S.
• Fussnoten: Gesehen am 26.10.2022
• Titel Quelle: Enthalten in: Organometallics
• Ort Quelle: Washington, DC : ACS Publ., 1982
• Jahr Quelle: 2011
• Band/Heft Quelle: 30(2011), 10, Seite 2790-2809
• ISSN Quelle: 1520-6041
• DOI: doi:10.1021/om200164f
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 182003156X

Abstract

A series of sterically and electronically fine-tuned, chelating diphosphine ligands were synthesized. The ligands are analogues of Triptyphos (TTP, 1), all based upon a variably 9,10-two-carbon-bridged 9,10-dihydroanthracene scaffold. These new TTP-type ligands were employed in the Ni(0)-catalyzed isomerization of 2-methyl-3-butenenitrile (2M3BN), one of the key steps of industrial adiponitrile production by the DuPont process. The reaction showed a surprising preference for ligands bearing electron-donating substituents, such as methoxy or methyl groups, in the phenyl para position of the Ni-ligating PPh2 units. Octyltriptyphos (3) afforded the highest 2M3BN-isomerization turnover rate yet reported. A series of deuterium-labeling experiments was performed to investigate the possibility of an isomerization mechanism consisting of a cascade of de- and rehydrocyanation steps, which could be excluded. Using the ethano-bridged ligand 4, complex 16a (4-κP:κP′)Ni(η3-C4H7)CN (supposedly an intermediate of the 2M3BN-isomerization reaction) was isolated, and its solid-state structure was determined by X-ray diffraction analysis. The complete catalytic cycle of 2M3BN isomerization with ligand 4, as suggested by the available experimental evidence, was modeled using DFT methods.