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8 results on '"Howlett, Michael G."'

5. Enantioselective reduction of -alkyl ketimines with frustrated Lewis pair catalysis using chiral borenium ions

Author

Mercea, Dan M., Howlett, Michael G., Piascik, Adam D., Scott, Daniel J., Steven, Alan, Ashley, Andrew E., Fuchter, Matthew J., and Engineering & Physical Science Research Council (EPSRC)

Subjects
Hydrosilylation, Chemistry, Multidisciplinary, B(C6F5)(3)-CATALYZED HYDROSILATION, IMINES, ACIDITY, BORANE, Borane, 010402 general chemistry, 01 natural sciences, Borylation, Catalysis, Frustrated Lewis pair, chemistry.chemical_compound, Materials Chemistry, Reactivity (chemistry), ASYMMETRIC HYDROGENATION, Science & Technology, 010405 organic chemistry, Chemistry, Organic Chemistry, Asymmetric hydrogenation, Metals and Alloys, Enantioselective synthesis, H BOND ACTIVATION, General Chemistry, HETEROCYCLIC CARBENE LIGANDS, Combinatorial chemistry, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, POLYMERIZATION, Physical Sciences, Ceramics and Composites, HYDROSILYLATION, BORYLATION, 03 Chemical Sciences, Carbene
Abstract

Effective enantioselective reduction of ketimines has been demonstrated by ‘frustrated’ Lewis pair catalysis using an IBiox-stabilised borenium cation., Enantioselective reduction of ketimines was demonstrated using chiral -heterocyclic carbene (NHC)-stabilised borenium ions in frustrated Lewis pair catalysis. High levels of enantioselectivity were achieved for substrates featuring secondary -alkyl substituents. Comparative reactivity and mechanistic studies identify key determinants required to achieve useful enantioselectivity and represent a step forward in the further development of enantioselective FLP methodologies.

Published
2019
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8. Kinetic Treatments for Catalyst Activation and Deactivation Processes based on Variable Time Normalization Analysis.

Author

Martínez-Carrión A, Howlett MG, Alamillo-Ferrer C, Clayton AD, Bourne RA, Codina A, Vidal-Ferran A, Adams RW, and Burés J

Abstract

Progress reaction profiles are affected by both catalyst activation and deactivation processes occurring alongside the main reaction. These processes complicate the kinetic analysis of reactions, often directing researchers toward incorrect conclusions. We report the application of two kinetic treatments, based on variable time normalization analysis, to reactions involving catalyst activation and deactivation processes. The first kinetic treatment allows the removal of induction periods or the effect of rate perturbations associated with catalyst deactivation from kinetic profiles when the quantity of active catalyst can be measured. The second treatment allows the estimation of the activation or deactivation profile of the catalyst when the order of the reactants for the main reaction is known. Both treatments facilitate kinetic analysis of reactions suffering catalyst activation or deactivation processes., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Published
2019
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