Sungjo Choi

Document Type

Thesis - University Access Only

Award Date

1996

Degree Name

Master of Science (MS)

Department / School

Chemistry and Biochemistry

First Advisor

David E. Lewis

Abstract

As a chiral auxiliary, the (IR)-3-endo-benzylisoborneol afforded relatively poor performance in asymmetric alkylation with 24 to 42% d. e.. In order to increase the diastereoselectivity of this alcohol, the steric bulk at the benzyl carbon must be increased. We chose to effect the increase in steric bulk by forming a symmetrical dimer through the reductive coupling of E-3-benzylidenecamphor in the presence of metal. Reduction with zinc was not effective, and no reaction occurred when the enone was heated with a freshly-prepared zinc-copper couple in the presence of trimethylchlorosilane. The reaction with magnesium and trimethylchlorosilane led to the formation of a mixture of (1R, 4S, 1'R) and (1R, 4S, 1'S)- 3-(1-chloro-1-phenyl)methyl-1, 7, 7, -trimethyl-2-trimethylsiloxy bicyclo[2.2.1 ]hept-2-ene (79) through a radical chain reaction; no dimeric compound was isolated from these reactions. The reductive condensation of E-3-benzylidenecamphor in the presence of sodium and trimethylchlorosilane led to dimeric compounds. We hypothesize that the reductive dimerization of the E-3-benzylidenecamphor proceeds through the monomeric chloride (79) by the Wurtz coupling of these halides by sodium metal.

Library of Congress Subject Headings

Reduction (Chemistry)
Chirality
Asymmetric synthesis

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright