Asymmetric synthesis of chiral organometallic compounds /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy Link to ProQuest copy |
| Abstract: | The feasibility of applying enzyme catalysis to the synthesis of chiral ferrocene compounds has been explored. R(-)-1-ferrocenylethyl propionate and S(+)-1-ferrocenylethanol were prepared in 84% ee via the irreversible transesterification of racemic 1-ferrocenylethanol with vinyl propionate in the presence of porcine pancreatic lipase. This represents one of the few known examples of enzymatic reactions of organometallic substrates and provides a route to the preparation of chiral ferrocene ligands since these compounds react with retention of configuration to form ferrocenylethylamine and other compounds. Our studies on the stereochemistry of Grignard reagents have shown that triphenyltin chloride, tert-butyl isocyanate, phenyl isocyanate and methyl chloroformate are useful electrophilic quenching agents for determining the diastereomeric purities of norbornylmagnesium bromide and bis-norbornylmagnesium. Reactions of norbornylmagnesium bromide and bis-norbornylmagnesium with these electrophilic reagents occurred with high chemical yields and retention of stereochemistry on the carbanionic carbon. The thermodynamic stability of norbornylmagnesium systems in ether was not significantly affected by the use of bulky alkoxy and amido ligands. Equilibrium constants ranged from 0.61-0.72 corresponding to 58-62% endo content of the ether solutions. However, the rate of inversion was lowered to 28% of the inversion rate of norbornylmagnesium bromide with the use of the dichelating ligand, 2-{[2-N,N-dimethylaminoethyl] N-methylamino}-ethanol. It has been shown that the rate of inversion could be effectively retarded through the use of sterically bulky dichelating ligands. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemistry." |
| Physical Description: | xii, 145 leaves ; 29 cm |
| Bibliography: | Includes bibliographical references. |