75804-84-1Relevant academic research and scientific papers
Thermodynamics of Vinyl Ethers. XXIV. Relative Stabilities and Structures of Some Isomeric Derivatives of Phenyl Vinyl Ether
Taskinen, Esko
, p. 203 - 208 (2007/10/02)
The relative stabilities of 2-aryloxy-4-methyl-1-pentenes (aryl = C6H5, 2-CH3-C6H4 and 2,6-(CH3)2-C6H3) and E and Z forms of the corresponding 2-pentenes have been determined by chemical equilibration in cyclohexane solution at several temperatures.The increasing steric requirements of the phenyl group following the introduction of o-substituents decrease the thermodynamic stability of the 2-pentenes relative to the 1-pentene.This result is explained by means of stereochemical changes in the phenyl vinyl ether skeleton caused by the o-substituents.The probable conformations of the isomeric forms are discussed on the basis of thermodynamic, 13C NMR and 1H NMR data.A re-estimation of the relative enthalpies of the gauche and s-cis rotamers of methyl vinyl ether suggests that the enthalpy of the former is ca. 23 kJ mol-1 higher than that of the latter instead of the enthalpy difference of 12 kJ mol-1 proposed earlier.
