Synthesis of biflavonoid frameworks using Suzuki-Miyaura coupling with boronic acids

Abstract

Importance of the work: Boronic acids were used in the Suzuki-Miyaura coupling
reaction to construct biflavonoid compounds.
Objectives: To investigate the use of boronic acids in the Suzuki-Miyaura coupling
reaction for biflavonoid synthesis.
Materials and Methods: Various methods were used, depending on molecularsymmetry.
A symmetrical 3′,3′′′-biapigenin framework was constructed using a center-to-edge
strategy. With the amentoflavone framework, the initial preparation of monoflavonoid
intermediates was followed by a sequence of reactions to form biflavonoid frameworks.
Results: A biapigenin structure, characterized by both A–B and B–B linkages, was
synthesized under the specified conditions. A comparative study with amentoflavone
revealed that boronic acids (ArB(OH)2) were effective under standard aqueous-basic
Suzuki-Miyaura coupling conditions.
Main finding: In the examined systems, Suzuki-Miyaura coupling reactions using
boronic acids proceeded, whereas the corresponding reactions using pinacol boronates
were unsuccessful.