Cascade Synthesis of 3-Alkenylcoumarins by Palladium-catalyzed Reaction of Phenols and Ethyl Propiolate

A highly effective cascade process giving 3-alkenylcoumarins is furnished by a series of reactions involving pallada-arylation of ethyl propiolate with phenols, intramolecular transesterification to 3-coumarylpalladium species, its alkyne insertion, and protonation. [Pd(OAc)(2)(dppe)] is an effective catalyst for the synthesis of 3-alkenylcoumarins from phenols and ethyl propiolate.