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DOI: 10.1055/sos-SD-026-00987

Marsden, S. P.Science of Synthesis, (2005261047.

Selenium dioxide is a popular reagent for the formation of allylic alcohols by allylic oxidation, as the reactions proceed without C=C bond migration and offer high and predictable regioselectivity.[‌13‌] Occasionally, direct conversion of an alkene into an unsaturated ketone is observed, though often this is formed as a mixture with the alcohol. For example, oxidation of 10 gives a mixture of ketone 11 and alcohol 12 (Scheme 3).[‌14‌] The ketones are presumed to be formed via the alcohol since the regioselectivities observed mirror those for the normal oxidation. Although benzeneseleninic anhydride is not generally active toward allylic oxidation, the corresponding 2-pyridyl reagent, which is generated in situ from di-2-pyridyl diselenide (14) and iodylbenzene, effects clean oxidation of alkenes to enones (e.g., 13 to 15), again apparently proceeding through the intermediate allylic alcohol.[‌15‌]

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