TY - JOUR
T1 - Barrier to rotation around the Csp2-Csp2 bond of the ketoaldehyde enol ether MeC(o)CH=CH-OEt as determined by 13C NMR and ab initio calculations
AU - Siebert, Hans Christian
AU - Tajkhorshid, Emad
AU - Dabrowski, Janusz
PY - 2001/9/20
Y1 - 2001/9/20
N2 - NMR measurements and ab initio calculations were applied to determine the barriers to rotation around formally single bonds of the title methyl-β-ethoxyvinyl ketone, i.e., the vinylogue of the ethyl ester of acetic acid. For comparison, ab initio calculations were performed for α,β-unsaturated, β-N, and β-S substituted ketones. The relative height of the rotational barriers for Csp2-Csp2 and Csp2-X bonds of the MeC(O)-CH=CH-X-alkyl(s) analogues was found to be reverse for X = N(alkyl)2 vs X = O-alkyl or X = S-alkyl. This finding is discussed in terms of differences in the electron density distribution in these molecules, resulting from differences in electron-donating properties of the heteroatoms N, O, and S.
AB - NMR measurements and ab initio calculations were applied to determine the barriers to rotation around formally single bonds of the title methyl-β-ethoxyvinyl ketone, i.e., the vinylogue of the ethyl ester of acetic acid. For comparison, ab initio calculations were performed for α,β-unsaturated, β-N, and β-S substituted ketones. The relative height of the rotational barriers for Csp2-Csp2 and Csp2-X bonds of the MeC(O)-CH=CH-X-alkyl(s) analogues was found to be reverse for X = N(alkyl)2 vs X = O-alkyl or X = S-alkyl. This finding is discussed in terms of differences in the electron density distribution in these molecules, resulting from differences in electron-donating properties of the heteroatoms N, O, and S.
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U2 - 10.1021/jp004476g
DO - 10.1021/jp004476g
M3 - Article
AN - SCOPUS:0035922575
SN - 1089-5639
VL - 105
SP - 8488
EP - 8494
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 37
ER -