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Smooth Photocatalytic Preparation of 2-Substituted 1,3-Benzodioxoles

Authors

  • Davide Ravelli,

    1. Department of Organic Chemistry, University of Pavia, Via Taramelli 10 (Italy), Fax: (+39) 0382-987316
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  • Prof. Angelo Albini,

    1. Department of Organic Chemistry, University of Pavia, Via Taramelli 10 (Italy), Fax: (+39) 0382-987316
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  • Prof. Maurizio Fagnoni

    Corresponding author
    1. Department of Organic Chemistry, University of Pavia, Via Taramelli 10 (Italy), Fax: (+39) 0382-987316
    • Department of Organic Chemistry, University of Pavia, Via Taramelli 10 (Italy), Fax: (+39) 0382-987316
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Abstract

A mild and general method for the synthesis of potentially bioactive 2-substituted-1,3-benzodioxoles is presented. This is based on the photocatalyzed activation of methylene hydrogen atoms in the presence of tetrabutylammonium decatungstate (TBADT). The method gave yields ranging from 46–77 % with no interference by benzene ring substituents, such as OR, COOMe, Me, or CHO. The OH group interfered, but protection regenerated the reactivity. 5-Chloro-1,3-benzodioxole was converted into a safrole derivative through a one-pot process involving two consecutive irradiations, at 366 nm for the photocatalyzed alkylation at position 2 and at 310 nm for the alkylation at position 5.

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