16195-58-7Relevant articles and documents
Noncatalytic organic synthesis using supercritical water: The peculiarity near the critical point
Ikushima, Yutaka,Hatakeda, Kiyotaka,Sato, Osamu,Yokoyama, Toshirou,Arai, Masahiko
, p. 2910 - 2914 (1999)
Pinacol and Beckmann rearrangements can be carried out effectively by using supercritical water (scH2O) both as an acid catalyst as well as a medium. In the near-critical region not only are the rates significantly accelerated (see picture), but the nature of supercritical water can be adjusted to give weak acidity, which opens a new reaction pathway to a Diels - Alder adduct between dehydrated products.
Factors Influencing Conformational Preferences in Cyclohexenes
Lambert, Joseph B.,Marko, Dale E.
, p. 7978 - 7982 (2007/10/02)
Conformational preferences have been measured for the first time for 4-substituted cyclohexenes in a solvent of low polarity.Measurements were made for the substituents Cl, Br, I, OH, OSiMe3, and CN and were compared with conformational preferences in cyclohexyl and exo-methylenecyclohex-3-yl.In the nearly nonpolar solvent CF2Cl2, in which intramolecular interactions are maximized, there is a much larger axial population for cyclohexen-4-yl than in cyclohexyl or exo-methylenecyclohex-3-yl.In particular, the dipolar interaction of the endocyclic double bond is reduced from that of the exocyclic double bond.This observation is confirmed by the almost negligible effect of symmetrizing the endocyclic double bond through 1,2-dimethyl substitution, in contrast with the large effect of symmetrizing the exocyclic double bond through 7,7-dimethyl substitution.Polar solvents increase the proportion of the axial conformer to a smaller extent for the endocyclic than for the exocyclic system, again in agreement with a lower dipolar effect in the endocyclic case.These results emphasize the anisotropic nature of the steric effects of double bonds.