2211-89-4Relevant academic research and scientific papers
Controlled oxidation of organic sulfides to sulfoxides under ambient conditions by a series of titanium isopropoxide complexes using environmentally benign H2O2 as an oxidant
Panda, Manas K.,Shaikh, Mobin M.,Ghosh, Prasenjit
experimental part, p. 2428 - 2440 (2010/06/18)
Controlled oxidation of organic sulfides to sulfoxides under ambient conditions has been achieved by a series of titanium isopropoxide complexes that use environmentally benign H2O2 as a primary oxidant. Specifically, the [N,N′-bis(2-oxo-3-R1-5-R2- phenylmethyl)-N,N′-bis(methylene-R3)-ethylenediamine]Ti(O iPr)2 [R1 = t-Bu, R2 = Me, R 3 = C7H5O2 (1b); R1 = R2 = t-Bu, R3 = C7H5O2 (2b); R1 = R2 = Cl, R3 = C7H 5O2 (3b) and R1 = R2 = Cl, R 3 = C6H5 (4b)] complexes efficiently catalyzed the sulfoxidation reactions of organic sulfides to sulfoxides at room temperature within 30 min of the reaction time using aqueous H2O 2 as an oxidant. A mechanistic pathway, modeled using density functional theory for a representative thioanisole substrate catalyzed by 4b, suggested that the reaction proceeds via a titanium peroxo intermediate 4c′, which displays an activation barrier of 22.5 kcal mol-1 (ΔG?) for the overall catalytic cycle in undergoing an attack by the S atom of the thioanisole substrate at its σ*-orbital of the peroxo moiety. The formation of the titanium peroxo intermediate was experimentally corroborated by a mild ionization atmospheric pressure chemical ionization (APCI) mass spectrometric technique. The Royal Society of Chemistry 2010.
Highly selective 30% hydrogen peroxide oxidation of sulfides to sulfoxides using micromixing
Noguchi, Takuya,Hirai, Yoshiro,Kirihara, Masayuki
scheme or table, p. 3040 - 3042 (2009/02/04)
The highly selective oxidation of sulfides to sulfoxides using 30% hydrogen peroxide has been achieved under catalyst-free conditions using a T-shaped micromixer. The Royal Society of Chemistry.
A General and Expeditious One-Pot Synthesis of Sulfoxides in High Optical Purity from Norephedrine-Derived Sulfamidites
Ruano, Jose L. Garcia,Alemparte, Carlos,Aranda, M. Teresa,Zarzuelo, Maria M.
, p. 75 - 78 (2007/10/03)
A general and simple procedure for preparing any kind of enantiomerically enriched sulfoxide starting from norephedrine-derived N-benzyloxycarbonylsulfamidite 3a is reported. After one-pot reaction of 3a with RMgX, HBF4, and R'MgX, a variety of sulfoxides 6 are obtained in ee usually higher than 93% and isolated yields ranging between 50 and 78%. The obtained configuration is tunable by simply electing the order of the addition of the reagents.
Oxygen Exchange between Sulphoxides and Sulphides. Part 3. The HCl-Catalysed Reduction of Aryl Methyl Sulphoxides by Dialkyl Sulphides in Aqueous Methanol
Miotti, Umberto
, p. 617 - 622 (2007/10/02)
Dialkyl sulphides reduce aryl methyl sulphoxides in aqueous methanol in the presence of ca. 4 mol dm-3 HCl.Ring substitution in phenyl methyl sulphoxides moderately affects their reactivity towards dibutyl sulphide, the overall effect resulting in a Hammett ρ value of -1.6.This parameter is a measure of the effect of structural changes on a protonation pre-equilibrium, the formation of chlorosulphonium ion, and its subsequent partitioning between reduction and return to reactants by the action of water.Changing the alkyl moiety of the sulphides induces moderate reactivity changes suggesting a compensation of opposite polar and steric effects.Sulphoxides with electron-releasing groups display the highest selectivity towards dialkyl sulphides.When a large concentration of sulphide is used, both racemization of chiral sulphoxide and 18O exchange with the aqueous solvent are suppressed and this suggests that the species ArR1SCl+ is a common intermediate for these processes and for the reduction reaction.These and other kinetic findings indicate that the reduction step involves the displacement at the ArR1SCl+ chlorine of a sulphide by a sulphide molecule rather than by chloride ion and rules out, for the racemization too, the hypothesis involving a free halogen intermediate.
Mechanism of the Reaction of Dialkyl Sulphides with Bromamine T in Alkaline Medium
Ruff, Ferenc,Kucsman Arpad
, p. 1075 - 1080 (2007/10/02)
Bromamine T (p-MeC6H4SO2NBr-K+) reacts readily with dialkyl sulphides (R2S) to yield sulphoxides (R2SO) and sulphimides (R2SNTs).The kinetics of the reaction were investigated in buffered alkaline water-methanol solutions.In rate-determining steps HOBr and p-MeC6H4SO2NHBr formed in equilibrium reactions convert dialkyl sulphides into bromosulphonium (R2SBr+) intermediates (ρ* -1.22 and 1.11, ρI -13.3 and -14.4, respectively.).Electrophilic additions of Br+ to sulphur atom are significantly hindered by the steric effect of S-alkyl groups (δ 0.713 and 0.765, ρs 0.766 and 0.792, respectively).Products are rapidly formed from bromosulphonium ions by nucleophilic displacement with OH- and p-MeC6H4SO2NH- nucleophiles.Product distribution depends on pH and the concentration of p-MeC6H4SO2NH2 but is not influenced markedly by S-alkyl groups in sulphides.Results are compared with those obtained earlier for chloramine T.
