Total Synthesis of (+)-Prezizaan-15-ol, (+)-Jinkohol II, and (+)-Jinkoholic Acid.

A recently developed photochemical cascade reaction provides access to diastereomeric pentacyclic products, which display the carbon skeleton of prezizane natural products. The minor diastereoisomer with a 2β-Me configuration was converted in 12 reaction steps into (+)-prezizaan-15-ol. The major diastereoisomer with a 2α-Me configuration gave in an analogous route (+)-jinkohol II, which was oxidized at C13 to (+)-jinkoholic acid.

Concise Total Synthesis of Agarozizanol B via a Strained Photocascade Intermediate.

The prezizane-type sesquiterpene agarozizanol B was synthesized employing a photochemical cascade reaction as the key step. Starting from a readily available 1-indanone with a tethered olefin, a strained tetracyclic skeleton was assembled which contained all carbon atoms of the sesquiterpene with the correct relative configuration. The conversion into the tricyclic prezizane skeleton was accomplished by a strategic cyclopropane bond cleavage.