title: Autoinduced catalysis and inverse equilibrium isotope effect in the frustrated Lewis pair catalyzed hydrogenation of imines.
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.
authors: Institute of Organic Chemistry, University of Paderborn, Warburger Straße 100, 33098 Paderborn (Germany).
authors: Sebastian
authors: S
authors: Tussing
authors: Institute of Organic Chemistry, University of Paderborn, Warburger Straße 100, 33098 Paderborn (Germany).
authors: Lutz
authors: L
authors: Greb
authors: Institute of Organic Chemistry, University of Paderborn, Warburger Straße 100, 33098 Paderborn (Germany).
authors: Sergej
authors: S
authors: Tamke
authors: Center for Multiscale Theory and Computation (CMTC) und Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster (Germany).
authors: Birgitta
authors: B
authors: Schirmer
authors: Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany).
authors: Claudia
authors: C
authors: Muhle-Goll
authors: Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany).|Department Magnetic Resonance of the Institute for Biological Interfaces, Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 (Germany).
authors: Burkhard
authors: B
authors: Luy
authors: Institute of Organic Chemistry, University of Paderborn, Warburger Straße 100, 33098 Paderborn (Germany). jan.paradies@uni-paderborn.de.
authors: Jan
authors: J
authors: Paradies
mesh_terms: D001596:Benzylamines / Q000737:chemistry; D001880:Boranes / Q000737:chemistry*; D002384:Catalysis; D003903:Deuterium / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D006865:Hydrogenation; D007097:Imines / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D001596:Benzylamines; D001880:Boranes; D007097:Imines; D058116:Lewis Acids; C098400:N-(1,1-dimethylethyl)benzylamine; D006859:Hydrogen; D003903:Deuterium
keywords: autoinduced catalysis; frustrated Lewis pairs; hydrogen activation; inverse equilibrium isotope effect; kinetics