Direct C-H cross-coupling approach to heteroaryl coumarins.

A Pd-catalyzed direct cross-coupling of 3-bromocoumarins with heteroarenes provided an efficient route to synthesizing 3-heteroarylcoumarins. The reaction scope for the transformation was fairly broad, affording modest to good yields of various 3-heteroarylcoumarin scaffolds, which are privileged structures and prevalent motifs in many biologically active compounds and fluorophores.