Synlett 2025; 36(05): 556-560
DOI: 10.1055/s-0043-1775392
letter

Hypervalent-Iodine-Mediated Base-Free Oxidative Olefination of Benzylic Amines to Access α,β-Unsaturated Ketones

Authors

  • Bapurao D. Rupanawar

    a   Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune-411008, India
    b   Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
  • Ajay H. Bansode

    a   Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune-411008, India
    b   Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
  • Gurunath Suryavanshi

    a   Chemical Engineering and Process Development Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune-411008, India
    b   Academy of Scientific and Innovative Research, Ghaziabad 201 002, India

B.D.R. and A.H.B. thank UGC, New Delhi, for awards of research fellowships. The authors would also like to thank CSIR, New Delhi [CSIR/21(1110)/20/EMR-II].


Graphical Abstract

Abstract

We report a one-pot base-free protocol for the oxidative olefination of benzylic amines promoted by a hypervalent iodine reagent for the synthesis of α,β-unsaturated ketones. Mechanistically, (diacetoxyiodo)benzene oxidizes the benzylic amine to the corresponding imine, which, on reaction with a phenacyl(triphenyl)phosphonium bromide salt and an in situ generated acetoxy anion leads to an α,β-unsaturated ketone. A wide range of α,β-unsaturated ketones were easily accessed through direct oxidative olefination of substituted benzylic amines in good to excellent yields and with high E-selectivity.

Supporting Information



Publication History

Received: 08 June 2024

Accepted after revision: 23 July 2024

Article published online:
22 August 2024

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