Studies on synthesis of spirolactone annulated bicyclo[2.2.2]octanes: tricyclic core of yaoshanenolides

A stereoselective approach to tricyclic core of yaoshanenolides from simple aromatic precursor is described. Cycloaddition of highly reactive spiroepoxycyclohexa-2,4-dienone, stereoselective Grignard reaction, alkylation, and ring-closing metathesis reaction are the key features of our approach.

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