<p> Deuterium tracer studies, kinetic isotope effect measurements
and product composition studies in both ammonia and ammonia-d3 have
been used to elucidate the mechanism of the y-elimination reaction of
3-phenylpropyltrimethylammonium iodide with potassium amide in liquid
ammonia at -55°. Deuterium tracer studies involving the products from
the reaction of 3,3-dideutero-3-phenylpropyltrimethylammonium iodide
have excluded the carbene and ylide mechanism. A deuterium exchange
test involving the deuterated quaternary salt in ammonia demonstrated
that a y-carbanion is formed during the reaction. In addition, a
large y-hydrogen isotope effect (kH/kD > 22) and a large nitrogen
isotope effect (k^14/K^15 = 1.022) were observed for the reaction.
These results are consistent with either an Elcb mechanism in which the
rates of ring closure and of return of the carbanion are of comparable
magnitudes or a concerted mechanism accompanied by an irrelevant
exchange reaction at the y-carbon. The latter has been eliminated on
the basis of a deuterium exchange test involving the undeuterated
quaternary salt in ammonia-d3 and the relative rates of y- and aelimination
of the deuterated and undeuterated quaternary salts in
both ammonia and ammonia-d3. </p> / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/21422 |
| Date | 08 1900 |
| Creators | Westaway, Kenneth |
| Contributors | Bourns, A. N., None |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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