Intramolecular Carbolithiation of 2,6-Dilithio-1,6-heptadienes: An Experimental and Theoretical Study
2,6-Dilithio-1,6-heptadienes 3 undergo intramolecular carbolithiation in Et2O/N,N,N′,N′-tetramethylethylenediamine (TMEDA) at the lithiated double bonds to afford 1,2-bis(lithiomethyl)cyclopentenes 5. Reaction of these dianions with electrophiles affords a number of 1,2-difunctionalized cyclopentene...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2007 |
| País: | España |
| Institución: | Universidad de La Rioja (UR) |
| Repositorio: | RIUR. Repositorio Institucional de la Universidad de La Rioja |
| OAI Identifier: | oai:portal.dialnet.es:doc/5bbc6829b750603269e803c4 |
| Acceso en línea: | https://investigacion.unirioja.es/documentos/5bbc6829b750603269e803c4 |
| Access Level: | acceso abierto |
| Palabra clave: | Ab initio calculations Carbanions Carbolithiation Cyclization Cyclopentenes |
| Sumario: | 2,6-Dilithio-1,6-heptadienes 3 undergo intramolecular carbolithiation in Et2O/N,N,N′,N′-tetramethylethylenediamine (TMEDA) at the lithiated double bonds to afford 1,2-bis(lithiomethyl)cyclopentenes 5. Reaction of these dianions with electrophiles affords a number of 1,2-difunctionalized cyclopentene derivatives 7-10. The ease of carbolithiation of 2,6-dilithio-1,6-heptadiene (3a) compared to that of 2-lithio-1,6-heptadiene (14) has been studied experimentally. A series of ab initio molecular-orbital calculations on the course of the reaction were carried out and the results were compared to those for the corresponding intramolecular carbolithiation of an isolated double bond. The Li-C interactions found in the transition state by this theoretical study support a carbolithiation pathway for the cyclization of 2,6-dilithio-1,6-heptadienes. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA. |
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