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

Abstract

Abstract 4‐Alkyl‐2,5,7‐cyclooctatrienols with high enantiomeric purities (93−96% ee ), obtained by an improved copper‐phosphoramidite‐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‐alkyl‐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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)