The crystal and molecular structures of fifteen α-cycloalkylacetophenones
and propiophenones have been determined
with the use of X-ray crystallography. All of the compounds
are known to undergo the Norrish type II reaction in the solid
state, which involves abstraction of a favourably oriented
Ƴ-hydrogen atom to yield a biradical which can undergo either
cleavage or cyclization. The compounds were studied to examine
the effect of variation in aromatic ring substituents and
cycloalkyl ring size on the nature and surroundings of the reaction
site, and, if possible, to develop structure-reactivity
relationships for reactions in the solid state.
Almost all of the acetophenone derivatives with simple
cycloalkyl rings studied assume a common conformation in the
solid state, with the acetophenone moiety occupying an
equatorial position on the cycloalkyl ring, and with the
Ƴ-hydrogen atom most likely to be abstracted utilizing a
boatlike abstraction geometry.
The effect of α-methyl substitution of the α-cycloalkylacetophenones
(to produce the corresponding propiophenones) is
to rotate the cycloalkyl moiety by approximately 100° about
the acyl-carbon α-carbon bond. The conformations of the cycloalkyl rings are in accord
with those expected. The cycloheptyl rings assume
twist-chairs (though somewhat disordered), while the cyclooctyl ring all display boat-chair conformations.
Four α-adamantylacetophenones assume similar conformations
in the solid state (with chair like abstraction
geometries), but small differences in conformation were found
to account for large differences in photochemical behaviour.
Structural studies of a 3-methyladamantyl derivative yielded
information as to the preferred pathways for cyclobutanol
formation in the solid state, and provided an opportunity for
producing an optically active product mixture from an achiral
starting. / Science, Faculty of / Chemistry, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41300 |
| Date | January 1986 |
| Creators | Evans, Stephen Vincent Ashley |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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