Carbon-13 and oxygen-18 kinetic isotope effects on methanolysis of p-nitrostyrene oxide
Kinetic isotope effects for the acid- and base-catalyzed methanolysis of (epoxide-/sup 18/O)- and (8-/sup 13/C)-p-nitrostyrene oxide have been measured at 30.0/sup 0/. In acid 94.7% of the reaction occurs at the benzylic carbon, while in base 83.5% occurs at the primary carbon (C(8)). In base the isotope effects kappa/sub 16//kappa/sub 1/( and kappa/sub 1/''/kappa /sub 1/number were 1.035 +/- 0.013 and 1.082 +/- 0.012, while in acid they were 1.012 +/- 0.011 and 0.995 +/- 0.012, respectively. These data complement previously determined deuterium isotope effects for the reaction in base. They suggest a late transition state in base with considerable ring opening via an S/sub N/2 mechanism. However, in acid, the data suggest a somewhat earlier transition state with less ring opening and weaker bonding to the nucleophile than in base.
- Research Organization:
- Univ. of Kansas, Lawrence
- OSTI ID:
- 5334040
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 108:7; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Regioselective ring opening of polycyclic aromatic hydrocarbon epoxides by polymer-supported N sub 3 sup minus anion
Epoxide ring opening with alcohols using heterogeneous Lewis acid catalysts: Regioselectivity and mechanism
Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
520200 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALKYLATED AROMATICS
AROMATICS
CARBON 13
CARBON ISOTOPES
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
DATA
EPOXIDES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LIGHT NUCLEI
MASS SPECTROSCOPY
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN 18
OXYGEN ISOTOPES
REACTION KINETICS
SPECTROSCOPY
STABLE ISOTOPES
STYRENE
SYNTHESIS