Base-Free β-Boration of α,β-Unsaturated Imines Catalysed by Cu2O with Concurrent Enhancement of Asymmetric Induction

Authors

  • Adam D. J. Calow,

    1. Centre for Sustainable Chemical Processes, Chemistry Department, Durham University, South Road, Durham DH1 3LE (United Kingdom)
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  • Cristina Solé,

    1. Dept Química Física i Inorgànica, University Rovira i Virgili, C/Marcel⋅lí Domingo s/n 43005 Tarragona (Spain), Fax: (+34) 977-559563
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  • Prof. Andrew Whiting,

    Corresponding author
    1. Centre for Sustainable Chemical Processes, Chemistry Department, Durham University, South Road, Durham DH1 3LE (United Kingdom)
    • Centre for Sustainable Chemical Processes, Chemistry Department, Durham University, South Road, Durham DH1 3LE (United Kingdom)
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  • Dr. Elena Fernández

    Corresponding author
    1. Dept Química Física i Inorgànica, University Rovira i Virgili, C/Marcel⋅lí Domingo s/n 43005 Tarragona (Spain), Fax: (+34) 977-559563
    • Dept Química Física i Inorgànica, University Rovira i Virgili, C/Marcel⋅lí Domingo s/n 43005 Tarragona (Spain), Fax: (+34) 977-559563
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Abstract

The stereoselective synthesis of γ-aminoalcohols from the catalytic asymmetric β-boration of α,β-unsaturated imine precursors has been streamlined with the use of Cu2O as the catalyst, readily accessible (R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl as the chiral ligand and no additional base. The new simplicity of the catalytic system has the added value of in situ formation of the imines, which allows access to cyclic and acyclic β-boryl imines. The reaction was followed by using in situ IR spectroscopy, which demonstrated the imine formation– β-boration sequence and that the new catalytic system is superior to those employed for this reaction previously.

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