title: Configurational stability of 2-benzoylcyclohexanone: unexpected solvent effects on the rate of racemization.
abstract: The kinetics of the racemization of 2-benzoylcyclohexanone 1 in hexanes, ethanol, and mixtures thereof have been investigated by time dependence of enantiomeric purity using enantioselective HPLC. In pure hexanes and ethanol, the racemization half-lives were determined as 552 and 23.8 min, respectively, at 66 degrees C. Surprisingly, racemization of 1 in mixtures of hexanes and ethanol was found to involve an induction period followed by a sigmoidal decrease of the enantiomeric excess with half-lives varying between 11.5 and 24.0 min. This unexpected solvent influence on the rate of racemization of 1 was attributed to complex isomerization mechanisms involving three possibly interconverting enol tautomers of 1.
authors.affiliation: Department of Chemistry, Georgetown University, Washington, DC 20057, USA.
authors.forename: Gilbert E
authors.initials: GE
authors.lastname: Tumambac
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Francis
authors.forename: Christian
authors.initials: C
authors.lastname: Wolf