Stereocontrolled Construction of Quaternary Stereocenters by Inter- and Intramolecular Nitro-Michael Additions Catalyzed by Bifunctional Thioureas

Authors

  • Rubén Manzano,

    1. Instituto CINQUIMA and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid. 47011 Valladolid, Spain, Fax: (+34)-98-342-3013
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  • José M. Andrés,

    1. Instituto CINQUIMA and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid. 47011 Valladolid, Spain, Fax: (+34)-98-342-3013
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  • María D. Muruzábal,

    1. Instituto CINQUIMA and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid. 47011 Valladolid, Spain, Fax: (+34)-98-342-3013
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  • Rafael Pedrosa

    Corresponding author
    1. Instituto CINQUIMA and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid. 47011 Valladolid, Spain, Fax: (+34)-98-342-3013
    • Instituto CINQUIMA and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid. 47011 Valladolid, Spain, Fax: (+34)-98-342-3013
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Abstract

A highly diastereo- and enantioselective conjugate addition of β-keto esters to nitroolefins, catalyzed by a chiral thiourea prepared from L-valine is described. The formation of two contiguous tertiary and quaternary stereocenters occurs in high yield and excellent diastereo- and enantioselection with only 2 mol% of catalyst loading. The reaction is general and different β-keto esters and aryl- and alkylnitroolefins have been tested. The same catalyst has been used to promote the first intramolecular conjugate addition leading to the cyclic adduct in moderate diastereoselectivity and good enantioselectivity.

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