Influence of the acetylenic substituent on the intramolecular carbolithiation of alkynes: a DFT theoretical study
| Autor: | Rudy Lhermet, Catherine Fressigné, Jacques Maddaluno, Muriel Durandetti, Anne-Lise Girard |
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| Přispěvatelé: | Chimie Organique et Bioorganique : Réactivité et Analyse (COBRA), Institut Normand de Chimie Moléculaire Médicinale et Macromoléculaire (INC3M), Institut de Chimie du CNRS (INC)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie Organique Fine (IRCOF), Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC) |
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Exothermic reaction
010405 organic chemistry Stereochemistry [CHIM.ORGA]Chemical Sciences/Organic chemistry Organic Chemistry Substituent Solvation chemistry.chemical_element 010402 general chemistry Triple bond 01 natural sciences 0104 chemical sciences chemistry.chemical_compound chemistry Computational chemistry Intramolecular force Propargyl Molecule Lithium |
| Zdroj: | Journal of Organic Chemistry Journal of Organic Chemistry, American Chemical Society, 2013, 78 (19), pp.9659-9669. ⟨10.1021/jo4012893⟩ |
| ISSN: | 0022-3263 1520-6904 |
| DOI: | 10.1021/jo4012893⟩ |
| Popis: | International audience; A theoretical study of the intramolecular 5-exo-dig carbolithiation of substituted propargyl o-lithioaryl ethers, leading to dihydrobenzofurans, has been performed. The results show that a DFT description of the reaction (B3P86, 6-31G**) matches the experimental data provided that an explicit solvation by two molecules of THF is considered. To take place, the cyclization also implies that the acetylenic chain adopts a conformation in which a significant interaction arises between the lithium and the C≡C triple bond. Reaching the cyclization TS requires the passage of an activation barrier that should not be higher than 12-13 kcal mol(-1). From a thermodynamic point of view, the reaction is exothermic whatever the substituent R (from approximately -40 to -62 kcal mol(-1)). In the starting substrate, a supplementary interaction between the Li and a substituent at the propargylic position can develop, influencing the future double-bond configuration. Thus, derivatives exhibiting an R-Li interaction tend to provide E olefins. In contrast, when no coordination between the lithium cation and the terminal R occurs, syn carbolithiation takes place, and the configuration of the exocyclic olefin is likely to be Z. This hypothesis accounts for most of the experimental results published before. |
| Databáze: | OpenAIRE |
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