Croatica Chemica Acta, Vol. 69 No. 4, 1996.
Izvorni znanstveni članak
Beta Secondary Deuterium Kinetic Isotope Effects on the Thermal Stereomutations of 1,2-Diphenylcyclopropanes
Lisa A. Asuncion
; Department of Chemistry, Syracuse University, Syracuse, New York 13244
John E. Baldwin
; Department of Chemistry, Syracuse University, Syracuse, New York 13244
Sažetak
(+)-(1S,2S)-trans-1,2-Diphenylcyclopropane and (-)-(1R,2R)-trans- l,2-diphenyl-3,3-t2-cyclopropane at 234 °C interconvert reversibly with the corresponding enantiomers and css-1,2-diphenyl cyclopropanes. For the unlabeled trans isomer, the ratio of rate constants for one-center epimerization (k\) and two-center turnover (&12) was found to be 1.1. A small normal k^Jk-Q effect, 3% per deuterium, was observed for the rate constant for one-center epimerization (k1); a substantial normal k-^lk-Q effect, 17% per deuterium, was observed for the rate constant for two-center turnover (k^). Thus different transition structures, presumably EF and EE 1,3-diphenyltrimethylene diradicals, dominate the two sorts of stereomutations.
Ključne riječi
Hrčak ID:
135980
URI
Datum izdavanja:
2.12.1996.
Posjeta: 952 *