[R2S-CH2-OTF](- AS A REAGENT WITH AN OPTIONALLY MONOSELECTROPHILIC ORBISELECTROPHILIC CSP(3) CENTER() OTF)

Sulfonium salts [R2S-CH2-OTf](+) OTf- 1a,b are synthetically versatile 1,1-biselectrophiles featuring the sulfonio- and triflato-substituent s as leaving groups of differential nucleofugic power. Reactions with a number of neutral nucleophiles \Nu yield a series of novel sulfoniom ethylated onium salts [R2S-CH2-Nu](2+) 2OTf(-) 2-8 under very mild con ditions. Structures of salts 2a, 5a and 6b were confirmed by X-ray ana lysis. With certain N-hetarenes exchange of both nucleofuges in la was achieved, yielding the symmetrical 1,1-bisonium salts 9 and 10. With pyridine(derivatives) selective substitution of the sulfoniofunction i n 1,1-bisonium systems 2a and 5a was also realized. These reactions re present typical examples of nucleophilic substitutions at geminally bi sonio substituted C-sp(3) centers, which we recently have introduced a s a novel variant of S(N)2 reactivity.