A Simple Biomimetic Synthesis of dl-Chamaejasmine, a Unique 3,3‘-Biflavanone

[Reaction: see text] The first chemical synthesis of dl-chamaejasmine (1), a structurally unique 3,3'-biflavanone natural product, was achieved as shown above, by a two-step sequence starting from trimethyl ether derivatives of 3-iodonaringenin (cis + trans) involving (i) metallic lanthanum-mediated reductive dimerization in refluxing THF and (ii) global demethylation with BBr3 in CH2Cl2. This synthesis represents a generally applicable biomimetic (reductive) radical dimerization approach to the 3,3'-biflavonoids.

Metabolites from in vitro cultures of Cassia didymobotrya

From suspension cultures of Cassia didymobotrya 7-acetylchrysophanol, chrysophanol-physcion-l0,l0'-bianthrone, (E)- and (Z)-3'-hydroxy-3,4,5'-trimethoxystilbene, (E)-4,3'-dihydroxy-3,5'-dimethoxystilbene and 7,4'-dihydroxy-3,5,3'-trimethoxyflavone have been isolated along with several known metabolites.