Dynamic Kinetic Resolution of ,-Unsaturated Lactones through Asymmetric Copper-Catalyzed Conjugate Reduction: Application to the Total Synthesis of Eupomatilone-3

摘要

Eupomatilones 1-7 are a family of lignans[1] isolated from the Australian shrub Eupomatia bennettii, found in the tropical and subtropical forests of New South Wales and Queensland.[2] All seven members of this family contain a highly oxygenated biaryl motif, as well as a cis orientation of the substituents at C4 and C5 of the butyrolactone ring. Of all the members of the eupomatilone family, there have only been three for which a total synthesis has been reported: eupomatilone-6, eupomatilone-4, and 3-epi-eupomatilone-6.[3] Despite this work, the total synthesis of enantiomerically enriched members of the eupomatilone family has remained an unsolved problem. Herein, we report the first asymmetric total synthesis of one member of the family, eupomatilone-3. The success of the synthesis was based on a highly efficient Suzuki-Miyaura cross-coupling,[4] along with a dynamic kinetic resolution[5] of an unsaturated lactone.