THE USE OF SHIFT REAGENTS AND 13C NUCLEAR MAGNETIC RESONANCE FOR ASSIGNMENT OF STEREOCHEMISTRY TO OXIMES

Authors
  1. Fraser, R.R.
  2. Capoor, R.
  3. Bovenkamp, J.W.
  4. Lacroix, B.V.
  5. Pagotto, J.G.
Corporate Authors
Defence Research Establishment Ottawa, Ottawa ONT (CAN);Ottawa-Carleton Inst for Research and Graduate Studies in Chemistry, Ottawa ONT (CAN);National Research Council of Canada, Ottawa ONT (CAN)
Abstract
The effects of the shift reagents (Eu(dpm)3 and Eu(fod)3 on the H and 13C nmr spectra of twelve oximes of diverse structure were examined. The proton data shows that the use of proton shifts to assign oxime stereochemistry, as has been done in the past, is unreliable. In contrast, Eu(dpm)3 causes LIS values for the 13C signals of alpha carbons which are strongly dependent on stereochemistry. Signals for all alpha carbons anti to the oxime oxygen experience large downfield shifts while all syn carbons are either unaffected or shifted upfield. Thus the effects of Eu(dpm)3 on 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.
Report Number
DREO-879 — Reprint
Date of publication
15 Mar 1983
Number of Pages
6
Reprinted from
Canadian J of Chemistry, vol 61, no 11, 1983, p 2616-2620
DSTKIM No
86-02998
CANDIS No
97694
Format(s):
Hardcopy;Originator's fiche received by DSIS

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