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Under similar literature conditions, tributyltin hydride-promoted free radical reaction of homopropargyl benzosulfonates 1 initiated a novel rearrangement sequence and led to formation of two kinds of cyclic sultones: 4-aryl-5,6-dihydro-1,2-oxathiin-2,2-dioxides 2 and 4-aryl-3-tributyltin-1,2-oxathiane-2,2-dioxides 7. Isolation and X-ray structure characterization of previously unreported cyclic α-tributyltin sultones 7 provided evidence for a cyclization-fragmentation-cyclization mechanism proposed by Motherwell.