Cycloaddition of Cyclohexa-2,4-dienones, Ring-Closing Metathesis, and Photochemical Reactions: A Common Stereoselective Approach to Duprezianane, Polyquinane and Sterpurane Frameworks

A novel approach to three different types of carbocyclic frameworks belonging to dupreziananes,
sterpuranes, and polyquinanes from simple aromatic precursors has been presented. Cycloaddition of
appropriately appended cyclohexa-2,4-dienones with acyclic dienes gave bridged bicyclic octanes suitably
disposed with olefinic chains, which upon ring-closing metathesis led to functionalized tricyclo[5.2.2.01,5]undecanes related to dupreziananes. Photochemical sigmatropic 1,2- and 1,3-acyl shifts in tricyclo[5.2.2.01,5]
undecanes upon triplet and singlet excitation provided stereoselective routes to sterpurane and polyquinane
frameworks.