R. Vijaya Anand, P. Saravanan, and Vinod K. Singh* Department of Chemistry, Indian Institute of Technology Kanpur-208016, India Fax +91 512590007; E-mail vinodks@iitk.ac.in Received 1 February 1999 ... Abstract: Aldehydes and ketones were thioacetalyzed using 1,2- ethanedithiol in the presence of a catalytic amount of Cu(OTf)2- SiO2 under solvent free conditions in excellent yields. Key words: thioacetalization, Cu(OTf)2-SiO2, aldehydes, and ke- tones