Rate and product studies in the solvolyses of methanesulfonic anhydride and a comparison with methanesulfonyl chloride solvolyses

Abstract

The specific rates of solvolysis of methanesulfonic anhydride have been measured conductometrically at −10 °C in 41 solvents. Use of the extended Grunwald–Winstein equation, with the NT scale of solvent nucleophilicity and the YOTs scale of solvent ionizing power, leads to sensitivity to changes in solvent nucleophilicity (ℓ value) of 0.95 and a sensitivity to changes in solvent ionizing power (m value) of 0.61, with a multiple correlation coefficient (R) of 0.973. Product selectivity values (S) in binary hydroxylic solvents favor alcohol attack in EtOH–H2O (a value of 1.2 in 90% EtOH rising to 4.0 in 40% EtOH) and in MeOH–H2O (a value of 3.7 in 90% MeOH rising to 6.0 in 50% MeOH). In 2,2,2,‐trifluoroethanol–H2O, the S values are much lower at about 0.1. Entropy of activation values are appreciably negative. Literature values for the specific rates of solvolysis of methanesulfonyl chloride have been extended to fluoroalcohol‐containing solvents (titrimetric method) and, at 45.0 °C, for an overall 43 solvents values are obtained (using NT and YC1 scales) of 1.20 for ℓ and of 0.52 for m (R = 0.969). It is proposed that both substrates solvolyze by an SN2 pathway. Copyright © 2007 John Wiley & Sons, Ltd.

Rate and Product Studies on the Solvolyses of Allyl Chloroformate

“…10-15 For the solvolysis of 3, the l/m value was calculated to be 2.3, which is similar to those of N,N-dimethyl sulfamoyl chloride ((CH 3 ) 2 NSO 2 Cl), 17 methylsulfonyl chloride (CH 3 SO 2 Cl), 22 dimethyl thiophosphorochloridate ((CH 3 O) 2 PSCl), 21 and N,N,N',N'-tetramethyldiamido-phosphorochloridate ((CH 3 ) 2 N) 2 POCl), 15 to suggest the existence of a S N 2 mechanism. The l/m value for the solvolysis of 3 (l/m = 2.3) is more similar to that of the corresponding reactions of ethyl chloroformate (l/m = 2.8, …”

Synthesis and Antimicrobial Studies of Tridentate Schiff Base Ligands with Pyrazolone Moiety and Their Metal Complexes

“…Additionally, for a number of substrates [2, 34, 42-48], there have been several instances where removal of the TFE-EtOH points have led to a considerable improvement of the goodness-of-fit parameters in Grunwald-Winstein linear free energy plots. Also presented in Table 4 are our correlation analysis results for 3, 4 , and 5 , with the exclusion of the data points in TFE-EtOH.…”

“…Solvents were purified and the kinetic runs carried out as described previously [42]. A substrate concentration of approximately 0.005 M in a variety of solvents was employed.…”

Isotope Effects in the Solvolysis of Sterically Hindered Arenesulfonyl Chlorides

“…Despite the existence of a large corpus of research on solvolytic processes near sulfonyl centers , details on the mechanism of this nucleophilic substitution remain unclear. A number of authors have proposed S N 2 or borderline S N 1–S N 2 mechanisms for this process . However, sterically hindered derivatives of aromatic sulfonic acids that contain o ‐alkyl groups show kinetic features that pose questions on the classical view of the bimolecular substitution mechanism .…”