Lewis Acid Activation of Carbodicarbene Catalysts for Rh-Catalyzed Hydroarylation of Dienes

• Published in: Journal of the American Chemical Society Vol. 137; no. 20; pp. 6488 - 6491
• Main Authors: Roberts, Courtney C, Matías, Desirée M, Goldfogel, Matthew J, Meek, Simon J
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 27.05.2015; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; HYDROGENATION; 1,3-DIENES; CARBODIPHOSPHORANES; INTERMOLECULAR HYDROARYLATION; HYDROAMINATION; LIGAND PROPERTIES; SELECTIVE HYDROARYLATION; EFFICIENT; HYDROHETEROARYLATION; UNACTIVATED ALKENES
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.5b03510

The activation of carbodicarbene (CDC)–Rh­(I) pincer complexes by secondary binding of metal salts is reported for the catalytic site-selective hydro-heteroarylation of dienes (up to 98% yield and >98:2 γ:α). Reactions are promoted by 5 mol % of a readily available tridentate (CDC)–Rh complex in the presence of an inexpensive lithium salt. The reaction is compatible with a variety of terminal and internal dienes and tolerant of ester, alkyl halide, and boronate ester functional groups. X-ray data and mechanistic experiments provide support for the role of the metal salts on catalyst activation and shed light on the reaction mechanism. The increased efficiency (120 to 22 °C) made available by catalytic amounts of metal salts to catalysts containing C(0) donors is a significant aspect of the disclosed studies.