Synthesis of Rigid Analogues of Flavone by Intramolecular Heck Reaction

A novel concise method to synthesize rigid analogues of flavone by an intramolecular Heck reaction with wide substrate scope was developed. The key intermediates 3‐(2‐bromobenzyl)‐4H‐chromen‐4‐ones were prepared easily in two steps. Most compounds were obtained with moderate to good yields (34–90 % yield, 19 examples). As the title reaction shows, rigid analogues of flavone were synthesized by an intramolecular Heck reaction from 3‐(2‐bromobenzyl)‐4H‐chromen‐4‐ones, which could be prepared easily in two steps. Most compounds were obtained with moderate to good yields.