515-46-8Relevant articles and documents
Nucleophilic Substitution at Sulphonyl Sulphur. Part 2. Hydrolysis and Alcoholysis of Aromatic Sulphonyl Chlorides
Ballistreri, Francesco P.,Cantone, ALfio,Maccarone, Emanuele,Tomaselli, Gaetano A.,Tripolone, Mario
, p. 438 - 441 (1981)
Kinetics of hydrolysis, methanolysis and ethanolysis of furan-2 and -3-, thiophen-2- and -3-, and benzene-sulphonyl chlorides have been measured.Fair correlations with Taft ?* values for heterocycles are found; more satisfactory trends are observed by applying the two-parameter (polar and steric) Taft-Pavelich equation, particularly for the hydrolysis reaction including data for aliphatic sulphonyl chlorides.In this case the negative δ value, which is related to the steric parameter, is consistent with steric acceleration due to relief of strain in the transition state.Alcoholysis rates of substituted thiophen-2-sulphonyl chlorides (5-CH3, 5-Cl, 4-NO2, and 5-NO2) have been also measured in order to compare the substituent effects with those already observed for hydrolysis.The data are in accord with previous findings, that an SN2 type mechanism takes place which is shifted toward an SN1 process (looser transition state) or an SAN process (tighter transition state) in the hydrolysis and alcoholysis reactions, respectively.
A kinetic study on nucleophilic displacement reactions of aryl benzenesulfonates with potassium ethoxide: Role of K+ ion and reaction mechanism deduced from analyses of LFERs and activation parameters
Um, Ik-Hwan,Kang, Ji-Sun,Shin, Young-Hee,Buncel, Erwin
supporting information, p. 490 - 497 (2013/03/13)
Pseudofirst-order rate constants (kobsd) have been measured spectrophotometrically for the nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzenesulfonates 4a-f and Y-substituted phenyl benzenesulfonates 5a-k with EtOK in anhydrous ethanol. Dissection of k obsd into kEtO- and kEtOK (i.e., the second-order rate constants for the reactions with the dissociated EtO - and ion-paired EtOK, respectively) shows that the ion-paired EtOK is more reactive than the dissociated EtO-, indicating that K + ion catalyzes the reaction. The catalytic effect exerted by K + ion (e.g., the kEtOK/kEtO- ratio) decreases linearly as the substituent X in the benzenesulfonyl moiety changes from an electron-donating group (EDG) to an electron-withdrawing group (EWG), but it is independent of the electronic nature of the substituent Y in the leaving group. The reactions have been concluded to proceed through a concerted mechanism from analyses of the kinetic data through linear free energy relationships (e.g., the Bronsted-type, Hammett, and Yukawa-Tsuno plots). K+ ion catalyzes the reactions by increasing the electrophilicity of the reaction center through a cyclic transition state (TS) rather than by increasing the nucleofugality of the leaving group. Activation parameters (e.g., ΔH? and ΔS?) determined from the reactions performed at five different temperatures further support the proposed mechanism and TS structures.
The SN3-SN2 spectrum. Rate constants and product selectivities for solvolyses of benzenesulfonyl chlorides in aqueous alcohols
Bentley, T. William,Jones, Robert O,Kang, Dae Ho,Koo, Sun
scheme or table, p. 799 - 806 (2010/06/16)
Rate constants for a wide range of binary aqueous mixtures and product selectivities (S) in ethanol - Water (EW) and methanol-water (MW) mixtures, are reported at 25 °C for solvolyses of benzenesulfonyl chloride and the 4-chloro - Derivative. S is defined as follows using molar concentrations: S =([ester product]/[acid product]) × ([water solvent]/[alcohol solvent]). Additional selectivity data are reported for solvolyses of 4-Z-substituted sulfonyl chlorides (Z - OMe, Me, H, Cl and NO2) in 2, 2, 2-trifluoroethanol-water. To explain these results and previously published data on kinetic solvent isotope effects (KSIEs) and on other solvolyses of 4-nitro and 4-methoxybenzenesulfonyl chloride, a mechanistic spectrum involving a change from third order to second order is proposed. The molecularity of these reactions is discussed, along with new term 'SN3-SN2 spectrum' and its connection with the better established term 'S N2-SN1 spectrum'. Copyright
