Date of Award
Doctor of Philosophy
A stable 1,1-dimethylsila-(alpha)-pyran-maleic anhydride Diels-Alder adduct was prepared and isolated in high yield. Thermolysis of this adduct in solution (150(DEGREES)C) afforded 1,2-dihydrophthalic anhydride and dimethylsilanone which was trapped with a variety of siloxanes. Irradiation of the adduct in ethereal solvents afforded benzene, CO(,2), CO, and dimethylsilanone which was again successfully trapped. This is the first reported example of direct photochemical silanone generation. Methyl(trimethylsilyl)silanone was generated from 1-methyl-1-trimethyl-silylsila-(alpha)-pyran in a similar fashion;Evidence for isomerization of methyl(trimethylsilyl)silanone to methyl(trimethylsiloxy)silylene was obtained upon pyrolysis (610(DEGREES)C) of 1,3,5,7-tetramethyl-1,3,5,7-tetrakis(trimethylsilyl)cyclotetrasiloxane. Methyl(trimethylsiloxy)silylene was trapped in high yield with butadiene. An independent generation of methyl(trimethylsiloxy)silylene, from thermolysis of 2-trimethylsilylheptamethyltrisiloxane at 620(DEGREES)C, indicated that it did not isomerize to methyl(trimethylsilyl)silanone. Instead, the silylene underwent (gamma)-CH insertion to afford 2,2,4-trimethyl-2,4-disilaoxetane which rapidly decomposed to methylsilanone, dimethylsilene, methylsilene, and dimethylsilanone;Photolysis of several silicon-substituted furans, in contrast to known alkyl furan photochemistry, resulted in clean isomerization to allenyl aldehydes and ketones in high yield. These allenyl carbonyl compounds proved to be thermally unstable. The allenyl ketones derived from 2,5-disilyl-substituted furans rearranged to isomeric furans at high temperatures or to stable enynols when heated in concentrated solutions;Irradiation of 2-silyl-substituted pyrroles afforded rapid and quantitative isomerization to 3-silyl-substituted pyrroles. 2,5-Disilylpyrroles photoisomerized to 2,3-disilyl pyrroles and to 3,4-disilyl pyrroles in high yield.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Gregory Paul Hussmann
Hussmann, Gregory Paul, "Synthesis and mechanistic studies of silaoxetanes and silanones " (1983). Retrospective Theses and Dissertations. 8482.