Gold-Catalyzed Cyclopropanation and the Synthesis of Komaroviquinone via Pt-Catalyzed Cyclization

Abstract

Part 1. Gold-Catalyzed Furanyl Cyclopropanation of Acyclic Conjugated Enynone

We developed an efficient cascade Au-catalyzed furanylation-cyclopropanation of acyclic enynones which bearing a double bond to the bicyclic compounds. This requires configurational change from the E-isomer to the Z-isomer prior to the furan formation. The intermediate formation was accomplished through 5-exo-dig manner and undergo cyclopropanation of double bond to furnish the product.

Part 2. Synthetic Study of Komaroviquinone via Pt-Catalyzed Cyclization

In 2010, the seniors in our group reported Pt-catalyzed hydrative cycloaddition of o-alkynylbenzaldehydes with an unsaturated bond and this methology has successfully served as a key step in total synthesis of a natural product faveline methyl ether that has [6.7.6] tricyclic skeleton. Encouraged by this result, we tried another synthetic study of koaroviquinone which was included in icetexane diterpenoid by utilizing pt-catalyzed hydrative cycloaddition as a key step.