Treatment of alkyl phenyl sulfoxides (2a-h) with O-methyl-O-tert-butyldimethylsily ketene acetal (1a) in dry acetonitrile in the presence of a catalytic amount of zinc iodide caused a Pummerer-type rearrangement to give α-siloxy phenyl sulfides (3a-h) under mild conditions. On the other hand, treatment of the sulfoxide (2d) with O-methyl-O-trimethylsilyl ketene acetals (1b, c) under similar conditions gave carbon-carbon bond-formed products, methyl 3-(phenylthio)-butyrates (8 and 9).