Cascade Reactions to Substituted 1 H -Pyrrole-3-carbonitriles via Ligand-Free Palladium(II)-Catalyzed C(sp)-C(sp 2 ) Coupling

An efficient and simple synthesis of substituted 1 H -pyrrole-3-carbonitriles was developed. This reaction is a palladium(II)-catalyzed cascade of C(sp)-C(sp (2) ) coupling followed by intramolecular C-N bond formation. The method can tolerate various substrates with satisfactory yields. Its ligand-free conditions and high efficiency make this method particularly attractive.