| Autor: |
Fraser, Robert R., Capoor, Raj, Bovenkamp, John W., Lacroix, Benoit V., Pagotto, Jack |
| Zdroj: |
Canadian Journal of Chemistry; November 1983, Vol. 61 Issue: 11 p2616-2620, 5p |
| Abstrakt: |
The effects of the shift reagents Eu(dpm)3and Eu(fod)3on the 1H and 13C nmr spectra of twelve oximes of diverse structure were examined. The proton data show that the use of proton shifts to assign oxime stereochemistry, as has been done in the past, is unreliable. In contrast, Eu(dpm)3causes LIS values for the 13C signals of α carbons which are strongly dependent on stereochemistry. Signals for all α carbons antito the oxime oxygen experience large downfield shifts while all syncarbons are either unaffected or shifted upfield. Thus the effects of Eu(dpm)3on these 13C signals provides an unambiguous method of configurational assignment to oximes. The effects of Eu(fod)3, though similar to Eu(dpm)3, were less consistent and thus less promising for making configurational assignments. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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