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Date Permissions Signed
5-29-2020
Date of Award
Spring 2020
Document Type
Masters Thesis
Department or Program Affiliation
Chemistry
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
O'Neil, Gregory (Gregory W.)
Second Advisor
Vyvyan, James R.
Third Advisor
Gilbertson, John D.
Abstract
Herein we report results from experiments aimed at better understanding SmI2(H2O)n reductions of allylic benzoates adjacent to a trisubstituted alkene. When flanked by both a chelating group and stereodirecting group, these reactions can occur with complete regioselectivity and good diastereoselectivity (up to 90:10). Initial experiments suggested that the reaction was stereospecific to alkene geometry. However, further experimentation has revealed that the alkene stereospecificity is substrate dependent. For instance, if the geminal alkene substituents are alkyl, results show the reaction to be stereospecific, but if one of the substituents is a phenyl group the reaction is still stereoselective but not stereospecific. This was demonstrated through the synthesis and subsequent SmI2(H2O)n reduction of a series of cis- and trans-allylic benzoate isomers followed by careful analysis of the product mixtures by 1H NMR. To explain these results our current working hypothesis is based on formation of an η3-organosamarium bicyclic intermediate. In some cases, C-C bond rotation in the pi-allyl intermediate relieves steric strain, leading to a loss in stereospecificity.
Type
Text
Keywords
allyl, organosamarium, stereospecific, stereoselective
Publisher
Western Washington University
OCLC Number
1156472034
Subject – LCSH
Samarium; Acrolein; Benzoates; Reduction (Chemistry)
Format
application/pdf
Genre/Form
masters theses
Language
English
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Recommended Citation
Leitch, Michael A., "Allylic Benzoate Reductions: A Study on Stereospecificity" (2020). WWU Graduate School Collection. 959.
https://cedar.wwu.edu/wwuet/959