The study started from thietane-3-one, a readily available inexpensive precursor that reacts as a typical ketone with Grignard or organolithium reagents for the preparation of thietanols 1, which were readily converted to thietane dioxides 2 by oxidation with mCPBA (Table ). Initial studies to generate the carbocation used thietanol dioxide 2a which was readily prepared by the addition of commercial 4methoxyphenylmagnesium bromide solution to thietane-3-one on >5g scale. Based on our previous conditions with oxetanols and azetidinols, 9a we then surveyed Lewis acids and Brønsted acids for the dehydrative generation of the benzylic carbocation on the thietane dioxide to trap with arene nucleophiles. Treating alcohol 2a with lithium salts in the presence of o-cresol under conditions successful for oxetanes formed the diarylthietane dioxide 3aa in low yield (Table ). A similar quantity of stable 3-aryl-2H-thiete 1,1-dioxide 4a was also formed, presumably through E1 elimination from the carbocation intermediate. On the other hand, Ca 2+ , Fe 3+, and H + catalysts all gave full conversion of the substrate and good yields of the diarylthietane dioxide product, but still with significant amounts of the elimination product 4a (entries 2-4). The solvent could be changed from dichloromethane to toluene as a more acceptable solvent for use on scale with similar results (entry 5, with Ca II catalyst). A preliminary reaction scope was then examined using the Ca-catalyst due to ease of handling, but less reactive substrates required elevated temperatures to initiate a reaction. Therefore, we reexamined higher temperature conditions on the model substrate 2a. Pleasingly the thietane dioxide derivatives displayed full stability under elevated temperatures in toluene and moreover gave a notable increase in yield and decrease in formation of the thiete dioxide side product. Using 110 ºC providing quantitative conversion,