Palladium-catalyzed synthesis of 2-allylindole and 2-allylbenzofuran derivatives from 2-((trimethylsilyl)ethynyl)arenes

A new protocol for the synthesis of 2-allylindole and 2-allylbenzofuran derivatives has been developed from readily accessible starting material, 2-((trimethylsilyl)ethynyl)arenes via Pd-catalysis. The presence of trimethylsilyl group in the alkyne is vital for this reaction. Stereoselectivity of 2-allylindole derivatives is controlled by the use of different nitrogen-protecting groups for 2-((trimethylsilyl)ethynyl)aniline. The CO2Me protection gives Z-isomers, whereas acetyl protection gives E-isomers.