Autoinduced Catalysis and Inverse Equilibrium Isotope Effect in the Frustrated Lewis Pair Catalyzed Hydrogenation of Imines |
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| Authors: | Dipl.‐Chem. Sebastian Tussing Dr. Lutz Greb Dipl.‐Chem. Sergej Tamke Dr. Birgitta Schirmer Priv.‐Doz. Claudia Muhle‐Goll Prof. Dr. Burkhard Luy Prof. Dr. Jan Paradies |
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| Affiliation: | 1. Institute of Organic Chemistry, University of Paderborn, Warburger Stra?e 100, 33098 Paderborn (Germany);2. Center for Multiscale Theory and Computation (CMTC) und Organisch‐Chemisches Institut, Westf?lische Wilhelms‐Universit?t, Corrensstrasse 40, 48149 Münster (Germany);3. Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz‐Haber‐Weg 6, 76131 Karlsruhe (Germany);4. Department Magnetic Resonance of the Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 (Germany) |
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| Abstract: | ![]()
The frustrated Lewis pair (FLP)‐catalyzed hydrogenation and deuteration of N‐benzylidene‐tert‐butylamine ( 2 ) was kinetically investigated by using the three boranes B(C6F5)3 ( 1 ), B(2,4,6‐F3‐C6H2)3 ( 4 ), and B(2,6‐F2‐C6H3)3 ( 5 ) and the free activation energies for the H2 activation by FLP were determined. Reactions catalyzed by the weaker Lewis acids 4 and 5 displayed autoinductive catalysis arising from a higher free activation energy (2 kcal mol?1) for the H2 activation by the imine compared to the amine. Surprisingly, the imine reduction using D2 proceeded with higher rates. This phenomenon is unprecedented for FLP and resulted from a primary inverse equilibrium isotope effect. |
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| Keywords: | autoinduced catalysis frustrated Lewis pairs hydrogen activation inverse equilibrium isotope effect kinetics |
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