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Updated: Jul 9, 2026

Light-driven Enzymatic Decarboxylation
Published on: May 22, 2016
Following the Molecular Mechanism of Decarbonylation of Unsaturated Cyclic Ketones Using Bonding Evolution Theory
Ehsan Zahedi1, Samaneh Shaabani1, Abolfazl Shiroudi2
1Chemistry Department, Shahrood Branch, Islamic Azad University , Shahrood, Iran.
Abstract:
The synergetic use of bonding evolution theory (BET) and noncovalent interaction (NCI) analysis allows to obtain new insight into the bond breaking/forming processes and electron redistribution along the reaction path to understand the molecular mechanism of a reaction and recognize regions of strong and weak electron pairing. This viewpoint has been considered for cheletropic extrusion of CO from unsaturated cyclic ketones cyclohepta-3,5-dien-1-one CHD, cyclopent-3-en-1-one CPE, and bicyclo[2.2.1]hept-2-en-7-one BCH by using hybrid functional MPWB1K in conjugation with aug-cc-pVTZ basis set. Decarbonylation of CHD, CPE, and BCH are nonpolar cyclo-elimination reactions that are characterized by the sequence of turning points (TPs) as CHD, 1-11-C[CC]C†C†FFFTSC†C†C†-0:HT + CO; CPE, 1-8-CC[C†C†F†][FF][FF]FTS[C†C†]-0:BD + CO; and BCH, 1-8-CC[C†C†]F[FF]FTS[C†C†]-0:CD + CO. Breaking of C-C bond between the terminal carbon atoms of diene/triene framework and carbon atom of CO fragment starts at a distance of ca. 1.9-2.0 Å in the vicinity of the transition structure where the transition states are not reached yet. NCI analysis explains that the noncovalent interactions between two fragments appeared after the breaking of C-C bonds.
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