Deciphering the stereoselectivity of Claisen rearrangements: joint density functional theory and machine learning models
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Data
2024-01-29
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Universidade Federal de Goiás
Resumo
In the present study, the stereoselectivity of Claisen Rearrangements was addressed,
focusing on the influence of two distinct electron-withdrawing groups and eight different
substituents in three variants of the rearrangement: Hurd, Eschenmoser, and Johnson.
Using the Curtin-Hammett principle, the energies of reactions, products, and transition
states were calculated using the M062X/def2TZVPP theory level. The results indicate
that kinetic effects predominantly govern the reaction equilibrium. A key aspect of
our investigation involved applying Shubin’s energy decomposition analysis to the optimized
transition states. This approach highlighted the significant influence of the electrostatic
component on stereoselectivity, revealing its predominance over the quantum
and steric components. Moreover, each transition state was divided into four fragments:
the electron-withdrawing groups (Ester and Nitrile), the specific Hurd/Esch/John group
(H, NMe2, and OEt), various substituents (alkyl and aryl), and the central fragment. This
fragmentation allowed for a comprehensive analysis of the dipole moments of the groups
and non-covalent interactions, providing insights into the electrostatic forces driving the
rearrangement process. In addition, Supervised Machine Learning algorithms were employed,
focusing on the analysis of electronic and geometric datasets related to the transition
states. The results obtained not only elucidate the mechanisms underlying the
stereoselectivity of Claisen Rearrangements but also provide a subtle understanding of
the interaction between different molecular components, establishing new perspectives
in advanced applications in organic synthesis.
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Rearranjos de Claisen , Estereosseletividade , Estado de transição , Teoria do funcional de densidade , Decomposição de energia , Aprendizado de máquina supervisionado , Claisen rearrangements , Stereoselectivity , Transition state , Density functional theory , Energy decomposition , Supervised machine learning
Citação
OLIVEIRA, A. G. C. Deciphering the stereoselectivity of Claisen rearrangements: joint density functional theory and machine learning models. 2024. 209 f. Tese (Doutorado em Química) - Faculdade de Química, Universidade Federal de Goiás, Goiânia, 2024.