Sila-Pummerer Reactions to Vinylsulfides

The thiazolidine-S-oxides 1184 are converted by Me3CSi(Me2)OTf 987/triethyla-mine, in up to 50% yield, into the thiazohne 1185 and the thiazolidine 1186, whereas reaction of 1184 (Ri, R2 = (CH2)s) with trimethylsilyl iodide 17/tri-ethylamine leads to 42% 1187 and, via ring enlargement, to 14% 1188 [19, 20]. 

Sulfoxides containing an a-chloro group 1191 or an a-trimethylsilyl group 1193 rearrange on silylation with TMSOTf 20/triethylamine or with LDA followed by TCS 14 to the olefins 1192 and 1194 in 86 and 75% yield and HMDSO 7 [22, 23], whereas a sulfoxide with an a-cyano or a-carbomethoxy group as in 1195 reacts 

Nucleophilic Substitutions and Cyclizations via Sila-Pummerer Reactions 

On heating DMSO with 2 equivalents of imidazole and hexamethyldisilazane (HMDS) 2, or of N-trimethylsilylimidazole 1219 [32], to 140-160°C the intermediate S-ylide 1220 adds to the imidazole to give N-methylthiomethylimidazole 1221 in 40-60% yield and HMDSO 7 and NH3 or imidazole [33]. The analogous reac- 

The ffl-amido-phenylsulfoxide 1233 cyclizes on reaction with TMSOTf 20/NEt3 via 1234 in 41% yield to the y9-lactam 1235 as well as in 8% yield to 1236 and 

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