Structure-Reactivity Relationship in the Frustrated Lewis Pair (FLP)-Catalyzed Hydrogenation of Imines

Sebastian Tussing; Karl Kaupmees; Jan Paradies

doi:10.1002/chem.201600716

Structure-Reactivity Relationship in the Frustrated Lewis Pair (FLP)-Catalyzed Hydrogenation of Imines

Chemistry. 2016 May 23;22(22):7422-6. doi: 10.1002/chem.201600716. Epub 2016 Apr 9.

Authors

Sebastian Tussing¹, Karl Kaupmees¹, Jan Paradies²

Affiliations

¹ Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany.
² Institute of Organic Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany. jan.paradies@uni-paderborn.de.

PMID: 27060884
DOI: 10.1002/chem.201600716

Abstract

The autoinduced, frustrated Lewis pair (FLP)-catalyzed hydrogenation of 16-benzene-ring substituted N-benzylidene-tert-butylamines with B(2,6-F2 C6 H3 )3 and molecular hydrogen was investigated by kinetic analysis. The pKa values for imines and for the corresponding amines were determined by quantum-mechanical methods and provided a direct proportional relationship. The correlation of the two rate constants k1 (simple catalytic cycle) and k2 (autoinduced catalytic cycle) with pKa difference between imine and amine pairs (ΔpKa ) or Hammett's σ parameter served as useful parameters to establish a structure-reactivity relationship for the FLP-catalyzed hydrogenation of imines.

Keywords: Hammett correlation; autoinduced catalysis; frustrated Lewis pairs; hydrogenation; imines.

Publication types

Research Support, Non-U.S. Gov't