Mechanistic Insights into the Iridium‐Catalyzed Hydrogenations of α, β‐Unsaturated Ketones. Issue 19 (31st August 2016)

• Record Type: Journal Article
• Authors: Engel, Julien; Mersmann, Stefanie; Norrby, Per‐Ola; Bolm, Carsten
• Is Part Of: ChemCatChem. Volume 8:Issue 19(2016)
• Page Start: 3099
• Page End: 3106
• Publication Date: 2016-08-31
• Subjects: alkenes -- density functional calculations -- hydrogenation -- iridium -- reaction mechanisms; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201600730
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: The highly enantioselective hydrogenation of linear enones catalyzed by Ir complexes that bear a chiral P, N ligand have been investigated computationally. Compared to the results of previous studies, the mechanism is different because of the coordination of the substrate. In the favored pathway Ir stays in the +3 oxidation state throughout the entire catalytic cycle, the olefinic group is coordinated trans to the ligand N atom, and the carbonyl group binds trans to a spectator hydride. After migratory insertion, a H2 coordinates and delivers the second H atom by σ‐metathesis. The calculated path rationalizes the observed enantioselectivities and allows the development of a predictive quadrant model for this class of substrate–ligand combination. Abstract : Which pathway? Highly enantioselective hydrogenations of linear enones catalyzed by Ir complexes that bear a chiral P, N ligand are investigated computationally. Compared to the results of previous studies, the mechanism is different because of the coordination of the substrate. The calculated path rationalizes the observed enantioselectivities and allows the development a predictive quadrant model for this class of substrate–ligand combination.