Regioselective phosphinylation of coumarins under green LED irradiation and its mechanism

The regioselective synthesis of 3-phosphinylated coumarins in moderate to excellent yields was developed via an EY/BPO-mediated cross-dehydrogenative coupling (CDC) reaction under green LED irradiation. The results of control experiments showed that the active intermediate, a P-centered radical, might be obtained through energy transfer and electron transfer processes.