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The infrared multiple-photon dissociation of several small organic sulfoxides was studied in order to provide some insight in the dissociative product channels for this class of molecules. Vibrational excitation was achieved with a TEA CO₂ laser and photofragments were identified with a laser ionized time of light mass spectrometer. A beam of 10.5 eV photons generated in a static xenon gas tripling cell from a tightly focused Nd:YAG third harmonic beam of light was used to ionize the molecules and fragment species. The photoionization mass spectra were found to contain fewer fragmentation species than the corresponding electron impact ionization mass spectra. Numerous product species were observed from skeletal rearrangement reactions despite the lower level of energy excitation from the photoionization process. The infrared photolysis wavelength dependence of dimethyl sulfoxide indicated that the maximum abundance for the major fragmentation species occurred at (or near) 1085.8 cm⁻¹. The major products at 1085.8 cm⁻¹ were [H₃CSO]⁺ and [CH₃]⁺. Minor products were also observed at a higher output power threshold like the skeletal rearrangement species [H₃CS]⁺ and [OCH₃]⁺. With the infrared photolysis wavelength dependence of methyl phenyl sulfoxide, the major product species ([CH₃]⁺ and [OSCH₃]⁺) had a maximum abundance near 1086.9 cm⁻¹ . Small mass fragment species (like [HCS]⁺, [C₄H₅]⁺ and [C₄H₃]⁺) had a maximum abundance near 1080 cm⁻¹ while large mass fragment species ([C₆H₈S]⁺ and [C₆H₅SO]⁺) had a maximum abundance that was further red-shifted (1058.9 and 1050.4 cm⁻¹ , respectively). The photolysis at 1085.8 cm⁻¹ generated the high mass fragment species ([C₆H₅SO]⁺, [C₆H₈S]⁺ and [C₅H₅S]⁺) at all CO₂ laser output powers but a plateau in the abundance was observed at higher output powers. The smaller mass fragmentation species only appeared after a threshold power was surpassed. The maximum abundance for the various fragmentation species of sec-butyl methyl sulfoxide occurred near 1072 cm⁻¹. The CO₂ laser output power dependence for the formation of the butane, butyl and butene ions indicated all three were generated at all output powers with an abundance plateau or decline occurring at higher output powers. Fragmentation species were observed from the butyl group primary products with the power threshold increasing for the sequentially smaller secondary species. / Graduate

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Thesis (Ph. D.)--Virginia Polytechnic Institute, 1966. / Vita. Abstract. Includes bibliographical references (leaves 121-125). Also available via the Internet.

The reaction between the lithium enolate of cyclohexanone and phenyl vinyl sulfoxide resulted in the formation of the novel bicyclooctanol sulfoxides 215-217 and the monoalkylated sulfoxide 218. The effects of variation in reaction time, temperature and concentration were studied. Under optimal conditions (10 minutes, -10°C and 0.085 M) the ratio of the bicyclooctanol sulfoxides 215-217 (75% yield) to the monoalkylated sulfoxide 218 was 95:5. The bicyclooctanol sulfoxides 215-217 were characterised as the sulfone derivatives, bicyclooctanol sulfones 219 and 220. X-ray crystal structures were used to determine the relative stereochemistry of the bicyclooctanol sulfoxides 215-217 and the bicyclooctanol sulfones 219 and 220. Bicyclo[4.2.0]octano-1-ol formation was determined to occur via an ionic mechanism. Mechanistic studies were carried out using variations in reaction lighting and reaction solvent, conducting the reaction in the presence of a radical trap and quenching the reaction with a deuterium label. The role of the counterion was determined to be important in the formation of the bicyclooctanol sulfoxides 215-217. Sequestering lithium ions with HMPA and substituting lithium with potassium favoured alkylation. Substituting the lithium enolate of cyclohexanone with the dimethylaluminium enolate of cyclohexanone resulted in a different distribution of the bicyclooctanol sulfoxides 215-217 and the formation of bicyclooctanol sulfoxide 243. Transition states to account for these differences have been proposed. The stability of the bicyclooctanol sulfoxides under conditions of acid, base and heating was studied. Thermal ring opening of the bicyclooctanol sulfoxides 215 and 216 to the monoalkylated sulfoxides 218A and 218B respectively occurred with retention of the configuration at sulfur. The relative stereochemistry of the individual bicyclooctanol sulfoxides 215-217 was considered to account for the observed stability in each case. The reaction between the lithium enolate of cyclohexanone and (R)-(+)-p-tolyl vinyl sulfoxide 193 gave the bicyclooctanol tolyl sulfoxides 246, 251 and 252 and the monoalkylated tolyl sulfoxide 247. This showed that both bond rotation in the side chain of the intermediate and epimerisation at sulfur occurred in the bicyclo[4.2.0]octan-1-ol forming process. The presence of the sulfoxide functionality in phenyl vinyl sulfoxide was determined to be crucial to the formation of bicyclo[4.2.0]octan-1-ols. In the reaction with the lithium enolate of cyclohexanone, phenyl vinyl sulfide gave no reaction, phenyl vinyl sulfone gave the bicyclic disulfones 260-265, ethyl acrylate gave the diesters 266-268 and diphenylvinylphosphine oxide gave the phosphine oxide 269. The cyclobutanol 270 and the ketone 271 were the products resulting from the reaction between the reaction between the lithium enolate of acetophenone and phenyl vinyl sulfoxide. This demonstrated potential scope for the cyclisation process using both cyclic and acyclic ketones.