24767-70-2Relevant articles and documents
Propanolysis of arenesulfonyl chlorides: Nucleophilic substitution at sulfonyl sulfur
Iazykov, Mykyta,Canle, Moisés,Santaballa, J. Arturo,Rublova, Ludmila
, (2017/09/08)
We have studied the mechanism of solvolysis of arenesulfonyl chlorides by propan-1-ol and propan-2-ol at 303-323 K. Kinetic profiles were appropriately fit by first-order kinetics. Reactivity increases with electron-donating substituents. Ortho-alkyl substituted derivatives of arenesulfonyl chlorides show increased reactivity, but the origin of this “positive” ortho-effect remains unclear. Likely, ortho-methyl groups restrict rotation around the C-S bond, facilitating the attack of the nucleophile. No relevant reactivity changes have been found with propan-1-ol and propan-2-ol in terms of nucleophile steric effect. The existence of isokinetic relationships for all substrates suggests a single mechanism for the series. Solvolysis reactions of all substrates in both alcohols show isokinetic temperatures (Tiso) close to the working temperature range, which is an evidence of the process being influenced by secondary reactivity factors, likely of steric nature in the TS. Solvation plays a relevant role in this reaction, modulating the reactivity. In some cases, the presence of t-Bu instead of Me in para- position leads to changes in the first solvation shell, increasing the energy of the reaction (ca. 1?kJ·mol?1). The obtained results suggest the same kinetic mechanism of solvolysis of arenesulfonyl chlorides for propan-1-ol and propan-2-ol, as in MeOH and EtOH, where bimolecular nucleophilic substitution (SN2) takes place with nucleophilic solvent assistance of one alcohol molecule and the participation of the solvent network involving solvent molecules of the first solvation shell.
α-,β-, and γ-Deuterium Isotope Effects in the Solvolysis of Octan-2-yl p-Bromobenzenesulphonate in 88percent Aqueous Trifluoroethanol and 83percent Aqueous Hexafluoroisopropyl Alcohol
Gregoriou, George A.,Varveri, Fannie S.
, p. 985 - 990 (2007/10/02)
Solvolysis of octan-2-yl p-bromobenzenesulphonate (1) and its α-2H1, β-2H3, β2H2 2)-(1)>, and γ-2H2 deuteriated derivatives in 88percent w/w aqueous trifluoroethanol and 83percent w/w aqueous hexafluoroisopropyl alcohol at 66 deg C gave isotope effects kH/kD of 1.154, 1.250, 1.503, and 0.997 and 1.174, 1.270, 1.553, and 1.000, respectively.These results when supplemented with those earlier reported in 65percent w/w aqueous ethanol represent a complete α- to γ-deuterium isotope effect spectrum in the solvolysis of a model secondary straight-chain alkyl system in aqueous hexafluoroisopropyl alcohol and a group of solvents covering a wide spectrum of nucleophilic ability and proposed as a model for the study of solvolytic reactions.The isotope effects increase in the order 65percent w/w ethanol 88percent w/w trifluoroethanol 83percent w/w hexafluoroisopropyl alcohol, corresponding to the decrease in the nucleophilic properties of these media.These trends are discussed in terms of Winstein's mechanistic scheme on one hand, and some features of our unified mechanism on the other.
