Origin of π-Facial Stereoselectivity in Thiophene 1-Oxide Cycloadditions
| Autor: | Nathan M. Gallup, Brian J. Levandowski, Dinushka Herath, Kendall N. Houk |
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| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular Molecular Conformation Oxide Thiophenes 010402 general chemistry 01 natural sciences Article Medicinal and Biomolecular Chemistry chemistry.chemical_compound Models Thiophene Envelope (waves) Cycloaddition Reaction 010405 organic chemistry Chemistry Organic Chemistry Molecular Oxides Stereoisomerism Cycloaddition 0104 chemical sciences Crystallography Quantum Theory Thermodynamics Stereoselectivity Ground state Selectivity Antiaromaticity |
| Zdroj: | The Journal of organic chemistry, vol 83, iss 5 |
| ISSN: | 1520-6904 0022-3263 |
| Popis: | We report a DFT computational study (M06-2X) of π-facial selectivity in the Diels-Alder reactions of thiophene 1-oxide. The preference for the syn cycloaddition arises because the ground state geometry of thiophene 1-oxide is predistorted into an envelope conformation that resembles the syn transition state geometry. The syn distortion occurs to minimize the effect of hyperconjugative antiaromaticity in the thiophene 1-oxide, arising from overlap of the σ*SO with the π-system. The syn selectivity follows through to the product structure that is stabilized by a π-σ*SO interaction, related to the 7-norbornenyl ion stability. |
| Databáze: | OpenAIRE |
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