Committee ChairGlass, Richard S.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractRing opening of tetraaryl thiirane cation radical was studied. The cation radical of tetraaryl thiirane generated photochemically undergoes C-C bond cleavage driven by inherent ring strain. This ring cleavage occurs in a stereospecific conrotatory manner at low temperature. However, this stereospecificity is lost when the reaction is conducted at room temperature. In this photoreaction between tetraaryl thiirane and tetracyanoethylene, (3+2) cycloadducts are obtained as a result of electron transfer, ring opening, back electron transfer, and 1,3-dipolar cycloaddition. A CIDNP experiment and γ-irradiation of 2,2-di-p-anisyl-3,3-diphenylthiirane were conducted to obtain more information about this reaction. Isomeric thiirane S-oxides were prepared to assign the structures of cis- and trans-2,3-di-p-anisyl-2,3-diphenylthiirane used in the stereochemical study of the ring opening reaction. These compounds readily decompose to the corresponding alkenes. This SO extrusion from thiirane S-oxide turns out to be a stereospecific elimination. Tetraaryl thiirane cation radical generated by anodic oxidation underwent C-S bond cleavage rather than C-C bond cleavage which resulted in production of the corresponding olefin. Further oxidation of this olefin under air produces two ketones resulting from C=C bond cleavage. In another approach to cleave the C-C bond of thiirane, ruthenium complexes of thiiranes were prepared but their decomposition did not occur with C-C bond cleavage of the thiirane ring.