Simple Synthetic Transformations of Highly Enantio-Enriched 4-Alkyl-2,5,7-cyclooctatrienols into Functionalized Bicyclo[4.2.0]octa-2,4-dienes and 2,6-Cyclooctadienones

摘要

4-Alkyl-2,5,7-cyclooctatrienols with high enantiomeric purities(93-96% ee),obtained by an improved copper-phos-phoramidite-catalyzed addition of dialkylzinc reagents to cyclooctatetraene monoepoxide,have been subjected to simple and practical manipulations.Simple esterification reactions are able to deliver new functionalized isomeric 8-al-kyl-7-acyloxybicyclo[4.2.0]octa-2,4-dienes through a domino sequence of rearrangement reactions,in good yields.Moreover,new 4-alkyl-substituted-2,6-cyclooctadienones with high optical purity can be efficiently obtained from gram-scale reactions by simple thermal treatment.