The biosynthesis of erysodienone involves a key step of oxidativephenol coupling. Starting with S-norprotosinomenine precursor A, cyclization via oxidative phenol coupling forms intermediate B, which in turn can be rearranged to form intermediate C. Hydrogenation of C forms the diphenoquinone intermediate E. An intramolecularMichael addition reaction converts E to the final product, erysodienone.[6]
A biomimetic synthesis route for erysodienone was developed based on a similar oxidative phenol coupling mechanism. Barton and co-workers[2] found that treating bisphenolethylamine precursor F with oxidants such as K3Fe(CN)6 initiated oxidative phenol coupling to form the 9-membered ring structure in intermediate D that itself undergo a Michael addition to give erysodienone.[7]
