Potassium hydroxide-mediated novel rearrangement of 2-alkyl-sulfonyl-2-arylsulfonyl-1-phenylethanones to 1-aryl-2-(arylsulfonylmethanesulfonyl)ethanones

Treatment of a solution of a mixture of 1-aryl-2-aryisulfonylethanones 9 and alkylsulfonyl chlorides (1.5-2.0 equiv) in THF at 0 degreesC with potassium hydroxide (8 equiv) for 10 min gave a rearrangement product, i.e., 1-aryl-2-(arylsulfonylmethanesulfonyl)ethanones 8, in excellent yields. Regiospecific methyl- and ethylation at the methylene carbon sandwiched between two sulfonyl groups of 8 could be achieved by the reactions of 7i-j with LDA (1 equiv) in THF at room temperature, respectively.