Alkenylation of Phosphacoumarins via Aerobic Oxidative Heck Reactions and Their Synthetic Application to Fluorescent Benzo­phospha­coumarins

Alkenylation of phosphacoumarins is developed from the reaction of phosphacoumarins with a variety of activated as well as nonactivated alkenes via aerobic oxidative Heck reactions. In addition, 3-alkenyl­phospha­coumarins undergo an inverse electron demand Diels–Alder reaction (IEDDA) with enamines in situ generated from ketone and pyrrolidine followed by 1,2-elimination and a dehydrogenation, producing fluorescent benzo­phospha­coumarins.