Molecular complexity from aromatics. Cycloaddition of cyclohexa-2,4-dienones, sigmatropic 1,2-acyl shift and ring-closing metathesis: a new, efficient, and stereoselective synthesis of (±)-hirsutic acid C and medium ring carbocycles

A new, stereoselective formal synthesis of hirsutic acid and medium ring carbocyclic systems from salicyl alcohol is described. Cycloaddition between electron deficient partners such as cyclohexa-2,4-dienone and methylmethacrylate, triplet sensitized 1,2-acyl shift and ring-closing metathesis are the key features of our approach.