Carbocyclization of unsaturated thioesters under palladium catalysis

An intramolecular thioester-olefin cross-coupling reaction for the preparation of cyclic ketone structures from unsaturated thioesters is described. This method capitalizes on the unique reactivity of thioesters with low-valent palladium catalysts and copper(I) salts to form acyl-metal species. Trapping of such intermediates with alkene functional groups generates the corresponding exo-methylene cycloalkanone products. Unsaturated thioester substrates, which can be accessed using a suite of modern synthetic methods, can now be regarded as precursors to complex carbocyclic derivatives.