Acetoxy group 1,2-rearrangements, vinyl

By contrast, diaslereomeric mixtures of 2-substituted 1-acetoxy-l-vinylcyclohexanes (or 1-ben-zoyloxy compounds) were found to rearrange stereoselectively to the 2-substituted ( )-2-ace-toxy (or benzoyloxy)ethylidenecyclohexanes under palladium(II) catalysis23. The stereochemical course of the reaction could be explained by the assumption that palladium(II) preferred to coordinate to the equatorial vinyl group anti with respect to the substituent at C-2. Both wnn -conformers, either from cis- or tram-substituted 1-acetoxy-l-vinylcyclohexene, furnished the same racemic cyclohexyl derivative with an -exocyclic double bond. 

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