Enhanced diastereoselectivity via confinement: Diastereoselective photoisomerization of 2,3-diphenyl-1-benzoylcyclopropane derivatives within zeolites
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Title |
Enhanced diastereoselectivity via confinement: Diastereoselective photoisomerization of 2,3-diphenyl-1-benzoylcyclopropane derivatives within zeolites
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Creator |
SIVAGURU, J
SUNOJ, RB WADA, T ORIGANE, Y INOUE, Y RAMAMURTHY, V |
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Subject |
mechanistic organic photochemistry
cation-pi interactions gas-phase cyclopropyl ketones rotational barriers amino-acid 1,2-diarylcyclopropanes n,n-dimethylformamide rearrangements complexes |
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Description |
Photochemistry of optically pure trans-2,3-diphenyl-1-benzoylcyclopropane has been examined in isotropic solution and within zeolites. Results suggest that it isomerizes by cleavage of either the C-1-C-2 or C-1-C-3 bond. From the perspective of chiral induction, photoisomerization of cis-2,3-diphenyl-1-benzoylcyclopropane derivatives with chiral auxiliaries placed at the meta and para positions of the benzoyl group have been examined both in isotropic solution and within zeolites. Whereas in isotropic solution the chiral auxiliaries placed at the meta position exhibit very little influence during the conversion of triplet cis-2,3-diphenyl-1-benzoylcyclopropane derivatives, they have significant influence within zeolites. For example, a-methyl benzylamine placed at the meta position of the benzoyl group (via an amide bond) yields the trans isomer with a diastereoselectivity (de) of 71% within NaY zeolite, whereas in solution no de is obtained. The chiral induction process within zeolites depends on the nature of the alkali ion and on the presence of water. Results suggest that the chiral auxiliary is able to control the bond being cleaved (C-1-C-2 VS. C-1-C-3 bond) within a zeolite, but it is unable to do so in an isotropic solution.
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Publisher |
AMER CHEMICAL SOC
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Date |
2011-07-14T01:26:14Z
2011-12-26T12:47:29Z 2011-12-27T05:35:05Z 2011-07-14T01:26:14Z 2011-12-26T12:47:29Z 2011-12-27T05:35:05Z 2004 |
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Type |
Article
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Identifier |
JOURNAL OF ORGANIC CHEMISTRY, 69(17), 5528-5536
0022-3263 http://dx.doi.org/10.1021/jo049697n http://dspace.library.iitb.ac.in/xmlui/handle/10054/3822 http://hdl.handle.net/10054/3822 |
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Language |
en
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