Studies on the synthesis of some new biflavanoids VII. Synthesis and structures of 2,2″‐biflavanones

A new approach to the synthesis of 2,2″-biflavanones by the reductive dimerization of flavones is reported. The products, the racemate and meso biflavanones, have been separated and their structures have been determined on the basis of their spectral data. The configuration of 3b has been determined by X-ray crystallography as well.