[893-69-6] · C14H15BF4S · Ethyldiphenylsulfonium Tetrafluoroborate · (MW 302.17)
Physical Data: mp 76-77 °C.
Form Supplied in: not commercially available.
Preparative Methods: there are two common methods of preparation. The first involves adding Silver(I) Tetrafluoroborate to a solution of Ph2S and Ethyl Iodide (5 equiv), and stirring the mixture for several hours (eq 1).5
The second method is a relatively new and unique technique.6 Under acidic conditions, the alkylation of aliphatic and aromatic sulfides has been carried out by using alcohols instead of alkyl halides (eq 2).
To a solution of ethyldiphenylsulfonium tetrafluoroborate in THF at -76 °C under nitrogen was added an appropriate alkyllithium, followed by 0.9 equiv of cyclohexanone. After stirring for 1 h and workup, the oxirane shown (eq 3) was obtained in good yield.7
If the carbonyl group is a,b-unsaturated, reaction takes place at the alkene to form substituted cyclopropanes.8 Meyers et al. have taken advantage of this and used ethyldiphenylsulfonium tetrafluoroborate to form 1,2,3-trisubstituted cyclopropanes (eq 4).3
Ethyldiphenylsulfonium tetrafluoroborate acts as a very powerful alkylating agent and converts phosphoric diesters to phosphoric triesters (eq 5).9 Ethyldiphenylsulfonium tetrafluoroborate also performs O-alkylation of amides10 and carboxylate salts.11
Tony Durst & Robert N. Ben
University of Ottawa, Ontario, Canada