BETA-KETO SULFOXIDES .4. CONVERSION INTO BETA-KETO SULFIDES, VINYL ETHERS, AND ENOL ACETATES

β-Keto sulfoxides are reduced with sodium metabisulfite to β-keto sulfides. Alkylation of the β-keto sulfide followed by reduction, O methylation, and base-catalyzed elimination in dimethyl sulfoxide solution yields the enol ether. Acylation of the keto sulfides by sodium hydride followed by acetic anhydride gives the enol acetate. Similar treatment of O-keto sulfoxides yields either the enol acetate or the α-acetoxy β-keto sulfide. Reaction of the salt of a β-keto sulfoxide with methanesulfinyl chloride yields a sulfone sulfide rather than the expected disulfoxide. A sulfone sulfide is also produced from the reaction of the enolate anion of acetylacetone or dibenzoyl-methane with two molecules of methanesulfinyl chloride. The formation of the sulfone sulfide is pictured as a base-catalyzed modification of the Pummerer reaction. © 1969, American Chemical Society. All rights reserved.