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2005
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In the Laboratory
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Circular Dichroism Investigation of Dess–Martin Periodinane Oxidation in the Organic Chemistry Laboratory
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Nicole A. Reed, Robert D. Rapp, Christian S. Hamann, and Pamela G. Artz
Department of Chemistry and Biochemistry, Albright College, Reading, PA 19604
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July 2005
Vol. 82 No. 7
p. 1053
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| Abstract |
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Using circular dichroism, organic laboratory students investigated the change
in absolute stereochemistry upon oxidation of menthol to menthone. In the first
laboratory period, the oxidation was performed with DessMartin periodinane,
which is a facile and less toxic oxidizing agent. Half the laboratory group
performed the oxidation with (–)-menthol and the other half used (+)-menthol
to produce (–)-menthone and (+)-menthone, respectively. The products
were analyzed in the second laboratory period using infrared spectroscopy and
gas chromatography/mass spectrometry to determine the fraction of starting
alcohol converted to ketone. Comparison was made between CD spectra both for
the menthol reactant and menthone product and for the (+)- and (–)-menthone
enantiomers. A large change in the CD spectrum from reactant to product was
diagnostic of successful oxidation. Additionally, the students observed that
the circular dichroism spectra of the two enantiomeric products, (–)-menthone
and (+)-menthone, are identical in shape but opposite in sign owing to the
distinct optical activity of these molecules. Pre- and post-evaluations, completed
by the students showed that the learning goal of exposure to CD spectroscopy
theory and methods for study of optically active molecules was successful overall.
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| Supplement |
Detailed student procedures questions, and instructor's notes are available.
The instructor's notes include: the synthetic procedure for Dess–Martin
periodinane; pre- and post-evaluation questions for assessment; IR spectra
for (+)-menthol, (–)-menthol, and a student-produced oxidation product
containing menthol and menthone; GC data for the product; chemical lists; and
equipment and lab protocol notes.
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JCE2005p1053W.doc (Microsoft Word)
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| More Information |
Citation |
Reed, Nicole A.; Rapp, Robert D.; Hamann, Christian S.; Artz, Pamela G. J. Chem. Educ. 2005 82 1053.
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Keywords |
Enantiomers; Hands-On Learning / Manipulatives; Instrumental Methods; Laboratory Instruction; Molecular Properties / Structure; Organic Chemistry; Oxidation / Reduction; Reactions; Second-Year Undergraduate
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History |
Created:
Last Updated: |
May 31, 2005
June 8, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2005
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July
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1053
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