Three-Component Reaction of 3-Formyl-6-Methylchromone, Primary Amines, and Secondary Phosphine Oxides: A Synthetic and Mechanistic Study.

A fast, mild, and efficient catalyst-free approach has been developed for the synthesis of chromonyl-substituted α-aminophosphine oxides by the three-component reaction of 3-formyl-6-methylchromone, primary amines, and secondary phosphine oxides at ambient temperature. Carrying out the reaction with aliphatic amines or aminoalcohols at a higher temperature (80 °C), phosphinoyl-functionalized 3-aminomethylene chromanones were formed instead of the corresponding chromonyl-substituted α-aminophosphine oxides. No reaction occurred when 3-formyl-6-methylchromone and secondary phosphine oxides were reacted with aromatic amines in the absence of any catalyst.