A Facile Method for the Bishomologation of Ketones to α,β-Unsaturated Aldehydes: Application to the Synthesis of the Cyclohexanoid Components of the Boll Weevil Sex Attractant

Abstract

Abstract The acid-catalyzed isomerization of tertiary vinyl carbinols (2) to the corresponding primary allylic alcohols (5) has been reported numerous times in the chemical literature.1 In addition, the corresponding acetylenic carbinols (3) have been shown2 to rearrange to α,β-unsaturated aldehydes (6) when treated with aqueous acid. Since yields are generally low under the conditions required for the latter transformation, a better method3 involves the isomerization of the corresponding tertiary acetylenic acetate (4) in the presence of silver ion to an allenic acetate, followed by hydrolysis to the desired α,β-unsaturated aldehyde (6).