Unstable carbanions. General acid catalysis of the cleavage of 1-phenylcyclopropanol and 1-phenyl-2-arylcyclopropanol anions

Journal Article · Wed Aug 15 04:00:00 EDT 1979 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00511a028· OSTI ID:5763186

Thibblin, A; Jencks, W P

Cleavage of the anion of 1-phenylcylopropanol to 1-phenylpropanone in aqueous solution, a reverse aldol-type reaction, is subject to general acid catalysis by protonated tertiary amines with ..cap alpha.. = 0.25, a primary deuterium (discrimination) isotope effect of k/sub H//k/sub D/ = 1.9 +- 0.2 for quinuclidine-H/sup +/ and water as proton donors to carbon, and a kinetic isotope effect of k/sub OH//k/sub OD/ = 1.22 +- 0.05. 1-phenyl-2-arylcyclopropanols cleave 10/sup 5/ times faster and show general acid catalysis with ..cap alpha.. less than or equal to 0.1 and an inverse kinetic isotope effect of k/sub OH//k/sub OD/ = 0.7 +- 0.1 that indicate less proton transfer in the transition state. The Hammett rho values for a small series of the cis and trans compounds are 5.0 and 4.0, respectively. It is concluded that these S/sub E/2 displacements and some related reactions proceed through preassociation and concerted mechanisms that are determined by the short lifetimes of carbanion intermediates.

• Research Organization: Brandeis Univ., Waltham, MA
• OSTI ID: 5763186
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 101:17; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400302* -- Organic Chemistry-- Isotope Effects-- (-1987)
ACETONE
CATALYSIS
DATA
DATA FORMS
DEUTERIUM
EXPERIMENTAL DATA
HYDROGEN ISOTOPES
INFORMATION
ISOLATED VALUES
ISOTOPE EFFECTS
ISOTOPES
KETONES
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
STABLE ISOTOPES