Synthesis of azaflavanones and alpha-ylidene azaflavanones

Azaflavanones are synthetic aza analogues of natural flavanones that have received attention in medicine. More recently, some alpha-ylidene azaflavanones have emerged as promising bioactive compounds. In the last decades, several approaches to synthesizing azaflavanones and alpha-ylidene azaflavanones have been described. These include intramolecular cyclizations of 2′-aminochalcones and analogues, coupling of 2-aminoacetophenones with aromatic aldehydes, metal-catalyzed coupling reactions of ortho-iodoanilines and the condensations of N-protected 2-aminoacetophenones and N-protected 2′-aminochalcones with aromatic aldehydes. This review discusses the different approaches in the racemic synthesis of azaflavanones and alpha-ylidene azaflavanones.