Palladium‐Catalyzed Direct Arylation of 4‐Chromanones: Selective Synthesis of Racemic Isoflavanones and 3,3‐Diaryl‐4‐chromanones

Abstract

Abstract For the first time, the synthesis of racemic isoflavanones has been achieved in satisfactory to good yields and with high selectivity by Pd‐catalyzed direct C‐3 arylation of 3‐unsubstituted 4‐chromanones with aryl bromides with the aid of a Pd 2 (dba) 3 / t Bu 3 PHBF 4 catalyst system in the presence of KHCO 3 as the base in a dioxane/water mixture (4:1). This catalyst system has also been employed in an unprecedented synthesis of 3,3‐diaryl‐4‐chromanones through direct arylation of 4‐chromanones in water.