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 2ß-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. A previous ambiguity regarding the configuration of the natural products could be clarified by total synthesis.