An Effective Synthesis of 5,4′-Disubstituted Flavones via a Cesium Enolate Assisted Intramolecular ipso-Substitution Reaction

A variety of 5,4'-disubstituted flavones, which are anticipated to be androgen receptor antagonists to treat diseases mediated by the androgen receptor, were synthesized. It was found that an intramolecular ipso-substitution reaction via cesium enolate using 2-fluoro-6-hydroxyacetophenone and various benzoyl chlorides was effective in the preparation of 5-hydroxy-4'-alkylflavones.