78377-94-3Relevant articles and documents
Enhanced Reactivities in Substitution and Elimination Reactions in Dimethyl Sulphoximide
Furukawa, Naomichi,Takahashi, Fujio,Yoshimura, Toshiaki,Morita, Hiroyuki,Oae, Shigeru
, p. 432 - 437 (2007/10/02)
The dielectric constants of dimethyl sulphoximide (DMSOI), tetramethylene sulphoximide (TMSOI), and dimethyl N-methylsulphoximide (N-MeDMSOI) were measured.The sulphoximides were tested as solvents for typical nucleophilic substitutions (SN2) and base-catalysed E2 reactions.The rates for several SN2 reactions and the activation parameters of the typical SN2 reaction between butyl bromide and sodium azide in DMSOI revealed that it behaves almost like a polar aprotic solvent despite the presence of the protic NH group.In a mixed solvent of DMSOI and MeOH, the rates of a few SN2 reactions were enhanced more than those in dimethyl sulphoxide-MeOH or dimethylformamide-MeOH.The rate enhancements of SN2 reactions in various mixed solvents appeared to be related to their pKa values.While the rate of the E2 reaction of 1-methylheptyl bromide with sodium methoxide or potassium t-butoxide in DMSOI is substantially higher (240 times) than that in methanol or t-butyl alcohol, the orientation of olefin formation in elimination from 2-substituted octanes in sulphoximides is similar to that in MeO(1-)-MeOH.Solvolyses of some alkyl tosylates and halides in DMSOI afforded the corresponding dimethyl N-alkyl sulphoximides in moderate yields.These results indicate that the sulphoximides belong to a new type of solvent which is protic in origin but also behaves almost like a characteristic polar aprotic solvent.
