Synlett
DOI: 10.1055/s-0043-1775392
letter

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

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
› Author Affiliations
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].


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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