Pseudopericyclic design drives antara-antara [1,5] methylene sigmatropic shifts from a stepwise to a concerted mechanism
Antara-antara [1,5]-methylene sigmatropic shifts of propenylidene cyclopropane and its heteroanalogues are shown to proceed through concerted or stepwise mechanisms depending on a delicate balance that is directly related to the presence or absence of heteroatoms at the termini atoms of the rearrang...
| Veröffentlicht in: | Journal of computational chemistry. - 1984. - 28(2007), 8 vom: 01. Juni, Seite 1411-6 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2007
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| Zugriff auf das übergeordnete Werk: | Journal of computational chemistry |
| Schlagworte: | Journal Article |
| Zusammenfassung: | Antara-antara [1,5]-methylene sigmatropic shifts of propenylidene cyclopropane and its heteroanalogues are shown to proceed through concerted or stepwise mechanisms depending on a delicate balance that is directly related to the presence or absence of heteroatoms at the termini atoms of the rearrangement. Lowering of activation energies upon heteroatom replacement are more significant for the oxacyclopropane analogues 1D, 1E, and 1F but double heterosubstitution is still needed to achieve a pseudopericyclic reaction. In fact only after reaching a pseudopericyclic process the energy balance favors the concerted pathway. Negligible NICS values and a clear disconnection in the ACID plot as well as some structural and energetical parameters reveal the pseudopericyclic nature of this concerted antara-antara [1,5](CH(2) ) sigmatropic shift. Although the product of the pseudopericyclic process is unprecedented, similar cycloisomerizations after allene activation should be considered within this hitherto undescribed reactions |
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| Beschreibung: | Date Completed 01.06.2007 Date Revised 17.04.2007 published: Print Citation Status PubMed-not-MEDLINE |
| ISSN: | 1096-987X |