Novel Diastereoselective Zirconocene-Mediated Ring-Contraction Reaction

Significance

Seven-membered cyclic enol ethers with an aryl group vicinal to the oxygen atom undergo a ring contraction reaction when treated with zirconocene. This reaction is unprecedented and enlarges the broad scope of possible applications for zirconocenes. The reaction allows a diastereoselective synthesis of cyclohexanol derivatives creating up to three new carbon-carbon bonds and four new stereogenic centers. Ring opening is not observed if the aryl ring is electron-deficient.