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Molecular Determinants for Rate Acceleration in the Claisen Rearrangement Reaction

Brickel, Sebastian and Meuwly, Markus. (2019) Molecular Determinants for Rate Acceleration in the Claisen Rearrangement Reaction. Journal of Physical Chemistry B, 123 (2). pp. 448-456.

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Official URL: https://edoc.unibas.ch/75024/

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Abstract

The Claisen rearrangement is a carbon-carbon bond-forming, pericyclic reaction of fundamental importance due to its relevance in synthetic and mechanistic investigations of organic and biological chemistry. Despite continued efforts, the molecular origins of the rate acceleration in going from the aqueous phase into the protein is still incompletely understood. In the present work, the rearrangement reactions for allyl-vinyl-ether (AVE), its dicarboxylated variant (AVE-(CO2)2), and the biologically relevant substrate chorismate are investigated in the gas phase, water, and in chorismate mutase. Only the rearrangement of chorismate in the enzyme shows a negative differential barrier when compared to the reaction in water, which leads to the experimentally observed catalytic effect for the enzyme. The molecular origin of this effect is the positioning of AVE-(CO2)2 and chorismate in the protein active site compared to AVE. Furthermore, in going from AVE-(CO2)2 to chorismate, entropic effects due to rigidification and ring formation are operative, which lead to changes in the rate. On the basis of "More O'Ferrall-Jencks" diagrams, it is confirmed that C-O bond breaking precedes C-C bond formation in all cases. This effect becomes more pronounced in going from the gas phase to the protein.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Physikalische Chemie (Meuwly)
UniBasel Contributors:Meuwly, Markus
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Chemical Society
ISSN:1520-6106
e-ISSN:1520-5207
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:30 Jun 2020 13:49
Deposited On:21 Feb 2020 11:56

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