Date of Award


Degree Type


Degree Name

Doctor of Philosophy


This thesis describes four topics in organic sulfur chemistry involving reactions of sulfonyl compounds with nucleophiles. In the first chapter the reactions of aromatic sulfonyl chlorides with amines in aqueous media were studied. The observed pH-yield profiles pointed strongly to the involvement at high pH of third-order processes leading to the sulfonamides. A new term {dollar}(k\sb{lcub}\rm NOH{rcub}){dollar} was introduced in the rate expression (eq 9) and the calculated pH-yield profiles from eq 10 gave a good agreement with experimental data. The increased value of rate constants with alkyl chain size of the amine, suggested aggregation of reactants due to hydrophobic interactions. This led to the proposal of reaction mechanisms, based on the initial complexation of reactants. The results of reactions of benzenesulfonyl chloride with amines in THF:H{dollar}\sb2{dollar}O further supported the proposed reactions. The practical applicability of the third-order processes has been demonstrated by synthesis of a number of sulfonamides in 1 M NaOH, using only a 5% excess of the sulfonyl chloride. These preparative reactions are milder versions of the Schotten-Baumann procedure.;In Chapter 2 the mechanisms of reactions of ethylene sulfone (thiirane 1,1-dioxide) with hydroxide in water, methoxide in methanol and ethoxide in ethanol have been examined, to obtain a clearer understanding of last stage of the Ramberg-Backlund reaction. For the hydroxide reaction. evidence has been obtained from kinetic and yield studies for two distinct pathways; first order and second order in hydroxide respectively. The reaction first order in hydkoxide is believed to proceed with attack of hydroxide on the sulfur to give a trigonal bipyramidal monoanion (5), while the reaction second order in hydroxide represents the further reactions of 5, either by simple deprotonation to give dianionic 6, or by further addition of hydroxide to give an octahedral intermediate 7.;Chapter 3 describes the new reactions of alkyl 2,2,2-trifluoroethanesulfonate esters (tresylate esters) with nucleophiles in aqueous basic media. The kinetic studies, product studies and alpha H-D exchange experiments showed that the reaction with water itself is the normal sulfonate ester hydrolysis, but that with hydroxide is a more complex process leading to the ester of sulfoacetic acid. The latter reaction evidently occurs by way of an (ElcB){dollar}\rm\sb{lcub}rev{rcub}{dollar} process with loss of HF from the tresylate ester to yield the 2,2-difluoroethenesulfonate ester, ROSO{dollar}\sb2{dollar}CH=CF{dollar}\sb2,{dollar} which upon Michael-type addition of hydroxide or added nucleophiles (amines and thiols) yields the observed products. A number of reactions of benzyl 2,2,2-trifluoroethyl sulfone were found to be similar to those of alkyl tresylates.;The mechanism of hydrolysis of 2,2,2-trifluoroethanesulfonyl chloride (tresyl chloride) has been examined and the results are described in Chapter 4. Kinetic studies, isotopic substitution studies, product analysis and primary kinetic isotope effects provide evidence that hydrolysis in the pH range 2-7 proceeds via the intermediate sulfene (CF{dollar}\sb3{dollar}CH=SO{dollar}\sb2){dollar} formed in an (ElcB){dollar}\rm\sb{lcub}irr{rcub}{dollar} reaction. In strong acid (2M D{dollar}\sb2{dollar}SO{dollar}\sb4){dollar} kinetics and alpha H-D exchange showed the sulfene formation to be an (ElcB){dollar}\rm\sb{lcub}rev{rcub}{dollar} reaction. The large primary solvent isotope effect suggests a possible transition state involving more than one water molecule for the initial deprotonation of tresyl chloride. (Abstract shortened by UMI.)



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.