Visible-light-promoted radical acylation/cyclization of alkynoates with aldehydes for the synthesis of 3-acylcoumarins.

A new, efficient, and atom-economic visible-light-promoted radical acylation/cyclization of alkynoates with aldehydes was developed for the synthesis of 3-acylcoumarins. The reaction undergoes a domino radical addition/5-exo cyclization, and ester migration to afford the product in moderate to good yields with wide functional group tolerance. The significant feature of this new method is the excellent tolerance of aliphatic aldehydes, which leads to the efficient synthesis of aliphatic 3-acylcoumarins.