Fiaud’s Acid: A Brønsted Acid Catalyst for Enantioselective Friedel− Crafts Alkylation of Indoles with 2‑Alkene-1,4-diones

Chatterjee, Sourav and Hintermann, Lukas and Mandal, Madhumita and Achari, Anushree and Gupta, Sreya and Jaisankar, Parasuraman (2017) Fiaud’s Acid: A Brønsted Acid Catalyst for Enantioselective Friedel− Crafts Alkylation of Indoles with 2‑Alkene-1,4-diones. Organic Letters, 19. pp. 3426-3429.

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    Abstract

    Fiaud’s acid (trans-1-hydroxy-2,5-diphenylphospholane 1-oxide), a phospholane-based phosphinic acid, is introduced as an efficient chiral Brønsted acid catalyst that mediates the asymmetric Friedel−Crafts alkylation of indoles with 2-butene-1,4-diones. With a catalyst loading of 10 mol %,the reaction proceeded smoothly to afford 2-(indol-3-yl)butane-1,4-diones in high yield (up to 82%) and high enantioselectivity(up to 91% ee, one such product showed enhanced ee of 98% after ecrystallization). The reaction conditions are sufficiently mild to tolerate sensitive functionality at room temperature and are therefore suitable for the synthesis of complex targets.

    Item Type: Article
    URI: http://www.eprints.iicb.res.in/id/eprint/2718
    Subjects: Chemistry
    Divisions: Indian Institute of Chemical Biology
    Depositing User: Ms Sutapa Ganguly
    Date Deposited: 08 Aug 2017 15:05
    Last Modified: 08 Aug 2017 15:05
    Official URL: http://dx.doi.org/10.1021/acs.orglett.7b01383
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