The greatly decreased reactivity of cyclic or, more especially, of spirobicyclic diaryldialkoxysulfuranes is probed in studies involving the isolation and characterization of a number of five-membered ring cyclic analogs of previously reported acyclic sulfuranes. The first reported ketal analog of a sulfone, spirodiaryldialkoxysulfurane oxide 9 is, like the spirosulfurane (3) from which it is prepared by oxidation with Ru04 or N204, inert toward boiling aqueous alkali or acid. In contrast, acyclic sulfurane oxide 21, or its ionic equivalent, postulated to be an intermediate in the reaction between diphenyl sulfoxide, chlorine, and KORF (where Rf is the hexafluoro-2-phenyl-2-propyl group) is very reactive. The observed products, ethers 23 and 24, are postulated to result from a reaction involving an O-alkylated diphenyl sulfone intermediate which generates a very good leaving group, diphenyl sulfone, in a reaction leading to a carbonium ion or its equivalent. The reduced reactivity of the cyclic or spirosulfuranes or sulfurane oxides relative to their acyclic analogs in hydrolysis reactions is thought to result from the fact that they react by a pathway involving a change from trigonal bipyramidal to tetrahedral geometry. This represents the converse of the change in geometry which has been postulated to be responsible for the great increase in reactivity reflected in hydrolyses of cyclic phosphate or sulfite esters.