Palladium-catalyzed propargylative and allenylative dearomatization of 2-(chloromethyl)thiophenes: remarkable effect of solvents

The reaction selectivity could be easily controlled by the use of different solvents. The use of a coordinating solvent led to the formation of a propargylic compound as the sole product, whereas the use of an uncoordinating solvent led to the generation of an allenic compound as the major product.