Allylic Oxidation with Selenium Dioxide

Se allylic oxidation mechanism

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The first step is a cycloaddition similar to the carbonyl ene reaction. The allylic seleninic acid produced in the first step undergoes a [2,3]-sigmatropic rearrangement to reinstate the double bond position. Rapid decomposition of the selenium (II) intermediate leads to an allylic alcohol. Oxidation continues to give the α,β-unsaturated carbonyl product.

A. Nakamura and M. Nakada, Synthesis (Stuttg)., 2013, 45, 1421–1451.

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