Highly Enantioselective Hydrogenation of N‐Aryl Imines Derived from Acetophenones by Using Ru–Pybox Complexes under Hydrogenation or Transfer Hydrogenation Conditions in Isopropanol |
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Authors: | Estefanía Menéndez‐Pedregal Dr. Mónica Vaquero Dr. Elena Lastra Prof. Pilar Gamasa Dr. Antonio Pizzano |
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Affiliation: | 1. Laboratorio de Compuestos Organometálicos y Catálisis (Unidad Asociada al CSIC), Departamento de Química Orgánica e Inorgánica, Instituto de Química Organometálica “Enrique Moles”, Universidad de Oviedo, 33006 Oviedo (Spain);2. Instituto de Investigaciones Químicas (IIQ) and Centro de Innovación en Química Avanzada (ORFEO‐CINQA), CSIC and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla (Spain) |
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Abstract: | The asymmetric reduction of N‐aryl imines derived from acetophenones by using Ru complexes bearing both a pybox (2,6‐bis(oxazoline)pyridine) and a monodentate phosphite ligand has been described. The catalysts show good activity with a diverse range of substrates, and deliver the amine products in very high levels of enantioselectivity (up to 99 %) under both hydrogenation and transfer hydrogenation conditions in isopropanol. From deuteration studies, a very different labeling is observed under hydrogenation and transfer hydrogenation conditions, which demonstrates the different nature of the hydrogen source in both reactions. |
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Keywords: | amines asymmetric catalysis hydrogenation ruthenium transfer hydrogenation |
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