Intramolecular Carbolithiation of 2,6-Dilithio-1,6-heptadienes: An Experimental and Theoretical Study

  1. Sanz, R. 1
  2. Ignacio, J.M. 1
  3. Rodríguez, M.A. 2
  4. Fañanás, F.J. 3
  5. Barluenga, J. 3
  1. 1 Universidad de Burgos
    info

    Universidad de Burgos

    Burgos, España

    ROR https://ror.org/049da5t36

  2. 2 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

  3. 3 Universidad de Oviedo
    info

    Universidad de Oviedo

    Oviedo, España

    ROR https://ror.org/006gksa02

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Revista:
Chemistry - A European Journal

ISSN: 0947-6539

Año de publicación: 2007

Volumen: 13

Número: 17

Páginas: 4998-5008

Tipo: Artículo

DOI: 10.1002/CHEM.200601863 SCOPUS: 2-s2.0-34250338944 WoS: WOS:000247219900029 GOOGLE SCHOLAR

Otras publicaciones en: Chemistry - A European Journal

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Resumen

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.