Reaction of hydroxyflavones with secondary phosphine chalcogenides in the CCl4/Et3N system: synthesis of a new family of phosphorylated flavonoids

Flavonoids (3-hydroxy-, 3-hydroxy-4′-methoxy-, 3-hydroxy-7-methoxy-, and 5,7-dihydroxyflavones) react with secondary phosphine chalcogenides in the CCl4/Et3N redox system (50-52 °C, 3-5 h) to afford chemoselectively the corresponding chalcogenophosphinates of the hydroxyflavones in 65-82% yield.