|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
1996
>
September
> |
|
In The Laboratory
|
|
|
|
A New Photochemistry Experiment,
A Simple 2+2 Photocycloaddition that Poses an Interesting NMR Problem
|
John T. Magner, Matthias Selke, Arlene A. Russell, Orville L. Chapman
Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90024-1569
|
|
September 1996
Vol. 73 No. 9
p. 854
|
|
|
|
|
|
|
| Abstract |
|
The cycloaddition of ß-nitrostyrene to 2,3-dimethyl-1,3-butadiene provides an extremely clean example of 2 + 2 cycloaddition. Evaporation of the solvent, hexane, and the excess diene gives the two isomeric products. Together with a Diels-Alder reaction, which is performed routinely in all organic labs, this 2 + 2 cycladdition provides a platform for learning about orbital-symmetry control of cycloaddition. The 200-MHz 1H NMR spectrum of the crude product provides the student with an excellent intellectual challenge. Students can deduce the regiochemistry of the process and the configuartion of each product. The can identify major and minor products and using integration can determine the ratio of products. The NMR spectrum also provides good examples of interesting magnetic resonance phenomena: accidental coincidence of peaks, a geminal coupling with J = 0, spin-spin splitting patterns, and damagnetic shielding of methyl protons by a cis-phenyl group. This laboratory exercise combines theory, technique, spectroscopy, and data interpretation.
|
|
| More Information |
 Citation |
J. Chem. Educ. 1996 73 854.
|
Keywords |
|
History |
Created:
Last Updated: |
September 21, 1999
February 21, 2006
|
|
|
|
|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
1996
>
September
> Page
854
|
|
|
| JCE HS CLIC |
|
Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
|
| Contributions Welcome |
| JCE welcomes your submission |
| Advertisers |
| In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first. |
| Be An Ambassador |
| Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants. |
|
