Part A. Chapter 1. The Sharpless epoxidation product from E-4-phenyl-2-butene-1-ol and diethyl D-tartrate was converted into L-($-$)-phenylalanine in three steps. After completion of the above synthesis Sharpless published an extensive study of the synthesis of $\alpha$-amino acids via essentially the same route. Therefore the project was abandoned. Optically active 2-arylpropionic acids such as 2-phenylpropionic acid, 2-napthylpropionic acid, and 2-(4-isobutylphenyl)-propionic acid (Ibuprofen) were synthesized in two steps from Sharpless epoxidation products. Part B. Chapter 2. The synthesis of 4-carboethoxy-4,6-dihydro-thieno (3,4-b) thiophene 5,5-dioxide and 4-phenyl analogue, precursors to thiophene xylylenes, are reported. Attempts to trap the carboethoxy substituted xylylene with electron rich or electron poor dienophiles failed and only dimers were produced. In contrast, the phenyl substituted xylylene gave moderate yields of Diels-Alder adducts in trapping experiments with dienophiles such as dimethylacetylene dicarboxylate, dimethyl fumarate, and benzoquinone. Chapter 3. Several additional examples of a conceptually new route to 1,3-dihydrobenzothiophene-2,2-dioxides from $\alpha$-diazo-$\beta$-sulfonyl esters via a formal rhodium carbenoid insertion into an aromatic C-H bond is reported. Our attempts to extend the scope of this reaction to include insertion into furan derivatives failed. We obtained very unusual furan ring opened products. When the same rhodium carbenoid reactions were carried out with $\alpha$-diazo-$\beta$-ketoamides, 2-hydroxy-3-acetylindole derivatives were formed. Chapter 4. In order to gain insight into the rhodium carbenoid reaction mechanism, the diazo precursors to 1,3-dihydrobenzothiophene-2,2-dioxide, 2-indanone, and 2-tetralone which were mono substituted at the ortho position of the aromatic ring were synthesized and the hydrogen/deuterium isotope effects were measured. The observed isotope effects ranged from 3.3-4.9. Furthermore, deuterium NMR indicated that scrambling had occurred during the cyclization step. These data have been interpreted to show that these rhodium carbenoid reactions should be considered as electrophilic aromatic substitution reactions.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/7955 |
| Date | January 1991 |
| Creators | Babu, Suresh Dhandayutham. |
| Contributors | Durst, T., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 236 p. |
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