On the Claisen Rearrangement of Allyl Ethyl Ketene Acetals Generated in situ via Benzeneselenenic Acid Eliminiation

Mixed acetals 7 of benzeneseleninylacetaldehyde, prepared by a simple 2-step procedure from mono- and bicyclic allylic alcohols 5 , undergo benzeneselenenic acid elimination to transient ketene acetals 8 which afford γ, δ-unsaturated esters 9 via the ester Claisen rearrangement (Scheme 2). Under the same conditions selenoxide 7h derived from benzyl alcohol 5h is converted back to benzyl alcohol with the concomitant formation of ethylphenylselenoacetate 12 .