Regioselective Synthesis of Tetrahydrothiochromen-5-ones via a One-Pot Three-Component Solvent-Free Domino Protocol

A highly efficient one-pot three-component regioselective synthesis of 4-aryl-3-aroyl-2-methylsulfanyl-4,6,7,8-tetrahydrothiochromen-5-ones has been developed by annulation of β-oxodithioesters with aldehydes and cyclic 1,3-diketones under solvent-free conditions promoted by P2O5. No cocatalyst or activator is needed in this protocol. The merit of this process is highlighted by its high efficiency of producing three new bonds and a stereocenter in one operation.