Ligand Exchange Reaction of Sulfoxides in Organic Synthesis. A Novel Method for Synthesizing Acetylenes from Carbonyl Compounds through β-Trifluoromethanesulfonyloxy Vinyl Sulfoxides

α-Sulfinyl ketones were prepared by the reaction of alkyl phenyl sulfoxide or chloromethyl p-tolyl sulfoxide with aldehydes or methyl esters in high yields, and were converted to acetylenes through β-trifluoromethanesulfonyloxy vinyl sulfoxides by the ligand exchange reaction of the sulfinyl group.