Asymmetric Synthesis by the Intramolecular Haloetherification Reaction of Ene Acetal: Discrimination of Prochiral Dienes in Cyclohexane Systems

抄録

A novel asymmetric synthesis of the cyclohexane derivative functionalized by some substituents has been developed from the diene acetals (1), prepared from the corresponding diene aldehyde and (+)-hydrobenzoin. The treatment of 1 with NBS in the presence of MeOCH₂CH₂OH predominantly afforded 2 in a stereoselective manner. Subsequent alkylation of the methoxyethoxy group produced the optically active cyclohexene compounds (3) in good yields. The stereoselective chemical modification of the remaining olefin in 3 was made by OsO₄-oxidation.