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]
^Barton, Derek H. R.; Potter, Christopher J.; Widdowson, David A. (January 1974). "Part XXIII: On the benzyltetrahydroisoquinoline origins of the Erythrina alkaloids". Journal of the Chemical Society, Perkin Transactions 1. Phenol oxidation and biosynthesis: 346–348.
doi:
10.1039/P19740000346.
ISSN1364-5463.
Castedo, Luis; Dominguez, Domingo (January 1989). "Chapter 4: Dibenzazonine Alkaloids". In Arnold Brossi (ed.). The Alkaloids: Chemistry and Pharmacology. Vol. 35. Academic Press. pp. 177–214.
Chou, Chun Tzer; Swenton, John S. (October 1987). "A convergent strategy for synthesis of Erythrina alkaloids". Journal of the American Chemical Society. 109 (22): 6898–6899.
doi:
10.1021/ja00256a079.
ISSN0002-7863.