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

Hans Christian Siebert, Emad Tajkhorshid, Janusz Dabrowski

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)8488-8494
Number of pages7
JournalJournal of Physical Chemistry A
Issue number37
StatePublished - Sep 20 2001

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry


Dive into the research topics of 'Barrier to rotation around the C<sub>sp2</sub>-C<sub>sp2</sub> bond of the ketoaldehyde enol ether MeC(o)CH=CH-OEt as determined by <sup>13</sup>C NMR and ab initio calculations'. Together they form a unique fingerprint.

Cite this