Molecular diversity from aromatics. A tandem oxidative dearomatization, cycloaddition and reactivity modulation in excited states: synthesis of tricyclo[5.3.1.01,5]undecanes and bicyclo[4.2.0]octanes from common precursors

Stereoselective route to tricyclo[5.3.1.01,5]undecane and bicyclo[4.2.0]octane ring systems present in the molecular structure of tricycloillicinone, cedrenoids and endiandric acid, elysiapyrones, respectively, is described. A tandem oxidative dearomatization of o-hydroxymethylphenol, π4s+π2s cycloaddition, reactivity modulation in excited state and ring-closing metathesis are the key features of our approach.