A series of gold(I)-catalyzed oxidative rearrangement reactions of alkynes using sulfoxides as stoichiometric oxidants are reported. The reactions are postulated to proceed through intermolecular oxygen atom transfer from the sulfoxide to gold(I)-carbenoid intermediates. Under the conditions for gold(I)-catalyzed oxidative rearrangement, 1,6-enynes are isomerized to cyclopropyl aldehydes, homopropargyl azides produce pyrrolones, acetylenic alpha-diazoketones form cyclic en-1,4-diones, and propargylesters produce 2-acyloxyenals.