Some substrates gave interesting and unexpected products (Scheme 4). With styrene, both vicinally dimesyloxylated product 23 and geminally dimesyloxylated product 24 formed in approximately equal yields. Interestingly, geminally dimesyloxylated products 25 (CCDC 2340475) and 26 were exclusive with trans-chalcone and ethyl-trans-cinnamate substrates. Literature reports of similar reactions with trans-chalcone claim vicinally disulfonoxylated products. Our results suggest that the product structures were misassigned and that these compounds are likely geminally disulfonoxylated. With both ethyl 4-pentenoate and methyl 3,3-dimethyl-4-pentenoate, lactone products 27 and 28 predominated, and only small amounts of the expected dimesyloxylated products were observed. With methyl styryl ketone, α-mesyloxylated product 29 was exclusive. With certain substrates, we observed a profound effect on product selectivity and distribution when the I(III) oxidant and/or sulfonic acid was varied (Scheme 5). For example, when N-(3-buten-1-yl)phthalimide was stirred with PhI(OPiv)2 and MsOH in CH2Cl2, the major product was the expected dimesyloxylated compound 30 accompanied by a minor amount of mesyloxy-hydroxy compound 31 (Scheme 5). This selectivity reversed with the use of PIFA as the oxidant! Finally, with the combination of Koser's reagent [PhI(OH)(OTs)] and pTsOH•H2O, dihydroxylated product 32 was exclusive.