The regio- and diastereoselectivity in the coupling of $ gamma$-substituted allylic bromides with aldehydes mediated by indium in water were examined and found to be dependent on the steric effect of the substituents on both the allylic bromides and the aldehydes. / Despite the efficiency with which indium mediates carbon-carbon bond formation between allyl halides and aldehydes in an aqueous environment, it is not without short-comings. Nitro-functionalised aldehydes were found to be susceptible to the reductive conditions of this aqueous indium Barbier-Type reaction. In this connection, bismuth was found to chemoselectively mediate the coupling of allyl halides with aldehydes in water in the presence of tetrabutylammonium halides. / The indium Barbier reaction in an aqueous medium was extended to include propargylic bromides. The coupling of aldehydes with propargylic bromides gave regioselectively either the homopropargyl alcohol or the $ alpha$-allenic alcohol depending on the $ gamma$-substituent of the propargylic bromides. / The regio- and stereochemical course of the indium-promoted coupling of $ gamma$-substituted allylic halides with aldoses (water soluble carbohydrates) has been investigated. The stereoselective generation of two new contiguous stereogenic centres has been applied to the synthesis of novel 2-substituted carbohydrates. The stereoselectivity of the reaction was explained on the basis of chelation of the allyl indium species with the $ alpha$-hydroxycarbonyl function. This gives syn selectivity for the $ rm C gamma$-$ rm C beta$ diol function in the product. The relative stereochemistry of the $ rm C beta$-$ rm C alpha$ linkage in the product is governed by the preferred geometry of the allyl indium species.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.40367 |
| Date | January 1996 |
| Creators | Isaac, Methvin B. (Methvin Benjamin) |
| Contributors | Chan, Tak Hang (advisor) |
| 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 | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001537751, proquestno: NN19733, Theses scanned by UMI/ProQuest. |
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