Date of Award
Doctor of Philosophy
The phenomenon of long-range coupling, which has been previously observed between hydrogen atoms and the spin probe in carbocyclic semidiones, is further investigated in Part I of this dissertation. The possibility of a homoconjugative interaction occurring between the spin probe and the hetero atom lone pair of aza and phospha bridge substituted bicyclic semidiones was studied. The lack of nitrogen or phosphorus hyperfine splitting constants (hfsc) in the ESR spectra of several aza and phospha bicyclic semidiones studied suggests that long-range interaction is not important in these systems, despite their correct geometries and highly rigid structures;The effect of substituents on the magnitude of the a(,7)('H)(,-anti) in 7-syn substituted bicyclic 2.2.1heptane-2,3-semidiones was also investigated. The effect was dramatically illustrated when both the syn-chloro and syn-fluoro substituted bicyclo 2.2.1heptane-2,3-semidiones showed an absence of any hfs by a(,7)('H)(,-anti);Part II of this dissertation proved that unsaturated organostannanes are capable of reacting via a free radical chain process. Allylstannanes were found to photochemically react via an S(,H)2' (bimolecular homolytic substitution with double bond transposition) or addition-elimination process with hetero atom-centered radicals from RSO(,2)Cl, RSSR and PhSeSePh to give allyl sulfones, sulfides and selendies, respectively, in good yields. The AIBN initiated or photochemical reaction of propargylstannanes with RSO(,2)Cl and polyhalogenomethanes also proceeded in similar free radical fashion to give regioselectively substituted propadienyl products;It was also found that alkenyloxystannanes could serve as aldehyde or ketone equivalents when reacted in an S(,H)2' mode with polyhalogenomethanes to produce (alpha)-polyhalogeno-methylated ketones or aldehydes.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Lourdes Lucas Herold
Herold, Lourdes Lucas, "Long-range interactions in bicyclic semidiones and the free radical reactions of unsaturated organostannanes " (1983). Retrospective Theses and Dissertations. 7720.