Ay tterbium(III) trifluoromethanesulfonate catalyzed one-pot three-component thia-Michael addition reaction of thiolate salts, organic halides, and a,b-unsaturated compoundsh as been developed for the formationo f carbon-sulfur bonds. In this study,p otassium thioacetate serves as the sulfur source in an ucleophilic substitution reaction, which is followed by aY b(OTf) 3 -catalyzed (OTf = trifluoromethanesulfonate) S-deacetylation and subsequent thia-Michael addition reaction. Three important pharmaceutical derivatives were successfully prepared by using the intramolecular version of this one-pot thia-Michael addition reaction. The advantages of this Yb III -catalyzed process include its operational simplicity,i ts capacity towards the preparation of structurally diverse products in 40-93 %y ield, itsu se of relativelyl ow toxic or nontoxic reagents, and its catalyst loading of only 1-2 mol %.Scheme1.Synthetic methods for thia-Michael addition (EWG = electronwithdrawing group, SDS = sodium dodecyls ulfate, Ts = para-toluenesulfonyl, and PEG = polyethylene glycol).