Restricted Rotation in Ortho-Fluorine Substituted Cyclopentadienone and Terephthalate Systems

Abstract

<p>Biphenyls and terphenyls systems exhibit rotational barriers with a bulky substituent in the ortho-position. In most cases this substituent has been methyl groups which give two distinct peaks in the 1H NMR spectrum due to the mixture of cis and trans diastereomers. The compounds 2,S-dicarboethoxy-3,4-bis{2fluorophenyl)cyclopentadienone and diethyl 2,3-bis{2-fluorophenyl)terephthalate were synthesized to observe the rotational barrier due to fluorine. The 1H and 13C NMR spectra show the occurrence of "cis" and "trans" isomers due to the restricted rotation caused by ortho-substituted fluorine.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 16, 2010</p>