A straightforward, regioselective, and step-economical ligand-free palladium-catalyzed decarboxylative functionalization of coumarin-3-carboxylic acids is devised. This protocol is compatible with a wide variety of electron-donating and-withdrawing substituents and allows for construction of various biologically important π-electron extended coumarins.
![ethyl 5-(3,4-dimethoxyphenyl)-2-[(7-methoxy-2-phenyl-1H-indol-3-yl)methylidene]-7-methyl-3-oxo-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate Structure](https://image.chemsrc.com/caspic/186/6468-44-6.png)
