Conjugate addition of 2-tributylstannyl-1,3-dithiane to alpha,beta-unsaturated ketones has been achieved by the combined use of Cu(OTf)(2) and Et3SiOTf in CH2Cl2 at room temperature. Thus, the corresponding beta-(1,3-dithian-2-yl)-substituted ketones were obtained in moderate to high yields under mild conditions.