Mechanism of the Deprotonation Reaction of Alkyl Benzyl Ethers with n-Butyllithium

Authors

  • Dr. M. Luz Raposo,

    1. Departamento de Química Física, Centro de Investigación en Química Biológica y Materiales, Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago (Spain), Fax: (+34) 981595012
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  • Dr. Fernando Fernández-Nieto,

    1. Departamento de Química Orgánica, Centro de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago (Spain)
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  • Prof. Luis Garcia-Rio,

    Corresponding author
    1. Departamento de Química Física, Centro de Investigación en Química Biológica y Materiales, Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago (Spain), Fax: (+34) 981595012
    • Departamento de Química Física, Centro de Investigación en Química Biológica y Materiales, Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago (Spain), Fax: (+34) 981595012

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  • Dr. P. Rodríguez-Dafonte,

    1. Departamento de Química Física, Centro de Investigación en Química Biológica y Materiales, Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago (Spain), Fax: (+34) 981595012
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  • Dr. M. Rita Paleo,

    1. Departamento de Química Orgánica, Centro de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago (Spain)
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  • Prof. F. Javier Sardina

    1. Departamento de Química Orgánica, Centro de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago (Spain)
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Abstract

Kinetic study of the α-lithiation of benzyl methyl ether (BME) by nBuLi has revealed that increasing the concentration of the organolithium compound does not necessarily increase the reactivity, and this is a consequence of the reactivities of the different nBuLi aggregates present in solution. We propose a dimer-based mechanism, in which a pre-complexation step is a key process for substrates bearing a donor oxygen atom that can interact with the lithium cation to form mixed dimers. For these studies, we have developed a system based on UV/Vis spectroscopy that allows kinetic measurements to be conducted at −80 °C under argon.

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