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Unprecedented α‐oxygenated β,γ‐unsaturated ketones bearing a quaternary carbon at the α‐position were synthesized in two steps from readily available α,β‐unsaturated ketones. The compounds were prepared on a gram scale under mild conditions via a key rearrangement step catalysed by 1 mol% of p‐toluenesulfonic acid as a low‐priced and sustainable catalyst. The olfactory properties of this novel family of odorants as well as of some derivatives have been assessed, revealing a quite broad odour spectrum and a pronounced susceptibility of the olfactory properties towards structural changes. Olfactory properties of a series of new compounds issued from an acid‐catalysed rearrangement of 2‐oxa diallylic alcohols. [ABSTRACT FROM AUTHOR]

Novel α‐quaternary allylic thioether ketones were efficiently prepared from readily available α,β‐unsaturated ketones in an easily scalable two‐step procedure, with an acid‐catalysed skeletal rearrangement of 2‐(vinylthio) allylic alcohols as the key step. The sensory properties of this novel class of sulfur odorants were evaluated and all displayed green herbal and vegetal notes. An unexpected and interesting fresh patchouli note was observed for an alcohol derivative. Olfactory properties of a series of new sulphur compounds issued from an acid‐catalysed rearrangement of 2‐(vinylthio) allylic alcohols. [ABSTRACT FROM AUTHOR]

The chemodivergent reactivity of bifunctional, enol thioether-containing diallylic alcohols in acidic medium is disclosed, highlighting the difference between strong Lewis acid and mild Brønsted acid catalysis. In the presence of bismuth(III) triflate, allylic alcohol activation affords diversely substituted cyclopentenones in a Nazarov-type electrocyclization, whereas activation of the thioenol ether by p-toluenesulfonic acid provides an entry to α-sulfenylated β,γ-unsaturated ketones. Both methods represent a facile access to the corresponding products under mild conditions, using inexpensive and non-toxic catalytic systems., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)