The chelating effect on regio- and stereochemical control of the homoallyl alcohol synthesis and electrophilic substitution of allylsilane was studied, using 2,2-dimethyl-1-$ {$1- ((S)-2-(2-methoxyethoxy)methyl) pyrrolidinyl$ }$-2-sila-4-pentene (S1) and 2,2-Dimethyl-1-$ {$1- ((S)-2-hydroxymethyl) pyrrolidinyl$ !$-2-sila-4-pentene (S2), with S1 synthesized from L-Prolinol. / The synthesis of homoallyl alcohol was carried out by allyl transformation from S1 and S2 to a Lewis acid activated aldehyde. Chelation between the allylsilyl ligand and the Lewis acid:aldehyde complex was found to favor the cyclic syn-clinal over the acyclic anti-periplanar transition state, in the asymmetric synthesis of the alcohol 1-dodecen-4-ol (P1). The bulky, remote and weak chelating ligand resulted in only modest selectivity and average chemical yield. / Regio- and stereochemical control of the electrophilic alkylation of allylsilanes S1 were achieved due to chelating effect that favored $ alpha$-alkylation. The chiral chelating ligand also resulted in enhanced stereochemical control electrophilic alkylation. Steric effect, due to a large electrophile, and solvent effect that causes disruption of the chelated complex, decrease $ alpha$-selectivity.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.60726 |
| Date | January 1992 |
| Creators | Nguyen, Thi-Ngoc Dieu |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001287774, proquestno: AAIMM74588, Theses scanned by UMI/ProQuest. |
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