Synthesis of Aryl Phosphines via Pd/C-Catalyzed Decarbonylation of Acylphosphines

C-P bond activation is attractive in the synthesis of trivalent phosphines, but not practical for high requirements in catalyst and reaction conditions. A synthesis of trivalent phosphines via Pd/C-promoted C-P bond activation and decarbonylation of acylphosphines was developed. The reaction was scoped across 31 examples, affording the corresponding trivalent phosphines in yields ranging from 21% to 98%. Pd/C was demonstrated as a more practical and robust catalyst than the previous Ni catalyst because of its higher catalytic activity, recyclability, and tolerance to air and moisture. Further studies on the Pd/C behavior indicated that the Pd/C primarily exerted its catalytic effect through dissolved Pd species, and Pd(II) in Pd/C played a more significant role than Pd(0). This research work not only represented a breakthrough in expanding the applicability of Pd/C catalysts but also marked an advancement in making C-P bond activation reactions more convenient and practical.