Palladium-catalyzed cycloisomerization of thiocarbamates with consecutive formation of quaternary carbon and sulfide

The Pd-catalyzed cycloisomerization of thiocarbamates with consecutive formation of a quaternary carbon and a sulfide is described. This Pd-catalyzed cascade reaction occurred with both alkylthiocarbamates and arylthiocarbamates, and arylthiocarbamates reacted faster than alkylthiocarbamates. The Pd-catalyzed cycloisomerization can be applied to phenylene- and alkylene-tethered substrates, and thiocarbamate was found to be less reactive than carbamimidothioate. The Pd-catalyzed cycloisomerization can be used to form bridged rings and is expected to be useful for ring construction of nitrogen-containing polycyclic natural products.