Paper based on a presentation at the 18th International Conference on Physical Organic Chemistry, Warsaw, Poland, 20–25 August 2006.
Rate and product studies in the solvolyses of methanesulfonic anhydride and a comparison with methanesulfonyl chloride solvolyses†
Article first published online: 5 APR 2007
Copyright © 2007 John Wiley & Sons, Ltd.
Journal of Physical Organic Chemistry
Volume 20, Issue 6, pages 431–438, June 2007
How to Cite
Kevill, D. N., Ryu, Z. H., Niedermeyer, M. A., Koyoshi, F. and D'Souza, M. J. (2007), Rate and product studies in the solvolyses of methanesulfonic anhydride and a comparison with methanesulfonyl chloride solvolyses. J. Phys. Org. Chem., 20: 431–438. doi: 10.1002/poc.1168
- Issue published online: 17 APR 2007
- Article first published online: 5 APR 2007
- Manuscript Accepted: 17 JAN 2007
- Manuscript Revised: 11 JAN 2007
- Manuscript Received: 25 OCT 2006
- methanesulfonic anhydride;
- methanesulfonyl chloride;
- extended Grunwald–Winstein equation;
- product selectivity;
- SN2 mechanism
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.