An efficient method for the one-pot production of thia-Michael adducts using thio acids, epoxides, and
electron-deficient alkenes is described. Epoxides quickly underwent nucleophilic ring-opening with thio
acids on the silica gel surface at room temperature under solvent-free conditions to yield b-hydroxy
thioester intermediates. After addition of an electron-deficient alkene and a catalytic amount of Et3N
to the reaction mixture, the b-acyloxy mercaptans were generated in situ and subsequently underwent
thia-Michael addition reactions to produce the corresponding adducts in good to excellent yields.