l%ePummerer marrangcmeni is widely used for the pepration of ~~ylox~u~&s from sulfoxidcs by tmatment of acid anhydrides, acids, or acid halides, t) Although the asymmetric Pummemr rcarrangemcnt is of sisnificant impmtance due to the chkal transfer from optically active sulfoxides to the u-carbon of the sulfur, the extent of asymmetric induction never exceeded 30 % e.e. This is probably due to the formation of a sulfurane intermediate and the dissociation of the intimate ion pair by ma&on with the generated acetate anion (cq. l).2) Although the addition of ~~c~lo~ylc~irni~ @CC) as an effezctive scavenger of acetic acid incmas& enantiosekctivity, the chemical yield significantly decrcascd3) and the Pummerer reaction of chkal beuzyl ~y~s~o~ in the pmsfmcc of DCC gave only the raccmic adduct.") Reocntly, we rrpted the first highly aSymmetric sihcun-induced Ptlmm~-type reaction of chii sulfoxiti using o-mBthyl-o-rerz-butyMylsily1 ketenc acetal (l), which gave chiral a-siloxysulfides under mild conditions in high yield (eq. 2).5) The main reason for this high asymmetric induction seems to be the absence of sulfurane formaton. Therefore, we now examined a novel asymmetric Pummercr ma&on using a similar type of acyl-is&t& reagent, ethoxy vinyl ester (Z), which is known as a powerful acylating reagent@ for active hydrqen compounds such as alcohols, amines, and carboxylic acids and found 2 caused the highly asymmetric Pummcmr rcarrangmtt of chiral sulfoxides (3) leading to a-acetoxysulfides (4). Treatment of R-3n with 2 in mfluxing (C&C& bcnxenc or tolucne gave chiral R-cs-acetoxysulfidc (R-4aa) in drably high CC. (Table 1). Obsctvcd t.e.'s and yields were higher than those of the report& asymmetric Pummcrcrrcarrangcment using acid anhy&idcs in all cases. Although the asymmetric induction of the pmsent asymmetric Pummemr reaction is slightly lower than the silii-indud Pummcmr reaction, it is quite interesting to incmase the ~~rne~c i~ucti~ by preventing the f~tion of the subkranc in-. The