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Dimethyl sulfoxide is a polar aprotic solvent. It supports reactions of anions with many organic electrophiles without providing an O–H proton.

oxidation of an alkyl halide or a related electrophile by dimethyl sulfoxide. An alkoxysulfonium intermediate undergoes base-promoted elimination to a carbonyl compound and dimethyl sulfide.

Silver(I) promotes iodide departure, with precipitation of AgI. The oxygen of dimethyl sulfoxide substitutes at the iodine-bearing carbon to form an alkoxydimethylsulfonium intermediate. Triethylamine removes the hydrogen on that carbon; collapse forms C=O and breaks O–S, releasing dimethyl sulfide. The result is ketone D by a Kornblum oxidation. In arrow terms, the C–H electrons form the carbonyl pi bond as the O–S bond breaks. The carbon bearing iodine becomes the carbonyl carbon; the existing bridged ether and acetonide are spectators. The iodine centre loses its tetrahedral stereochemistry because it becomes trigonal planar.