Kinetics and mechanism of hydration of strained bridgehead bicyclic olefins. [Bicyclo (4. 2. 1) non-1(8)-ene and bicyclo (3. 3. 1)non-1-ene; proton transfer]

Journal Article · Wed Mar 17 00:00:00 EST 1976 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00422a046· OSTI ID:7193400

Chiang, Y; Kresge, A J; Wiseman, J R

Appreciable solvent isotope effects in the normal direction were found for the hydronium ion catalyzed hydration of bicyclo(4.2.1)non-1(8)-ene and bicyclo(3.3.1)non-1-ene (k/sub H/sup +///k/sub D/sup +// = 2.1 and 2.5, respectively), and reaction of the latter substrate also showed general acid catalysis with isotope effects for the general acids in the range 3.6 to 5.8. This is taken to mean that these strained olefins hydrate by the same mechanism as simple unstrained alkenes; rate-determining proton transfer from the catalyst to the substrate is followed by rapid hydration of the ensuing carbonium ion. The transition states in the reactions of the strained substrates, however, are significantly earlier than the very late ones characteristic of the protonation of unstrained olefins, and the present results lead to the estimate that, of the 12 kcal/mole of strain which the bridgehead double bond introduces into bicyclo(3.3.1)non-1-ene, 5 kcal/mole is still left in the protonation transition state whereas only 1.6 kcal/mole exists in the bridgehead cation. (auth)

• Research Organization: Illinois Inst. of Tech., Chicago
• OSTI ID: 7193400
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 98:6
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKENES
HYDRATION
DEUTERIUM
ISOTOPE EFFECTS
CATALYSIS
CHEMICAL REACTION KINETICS
INTERMEDIATE STRUCTURE
STRAINS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
REACTION KINETICS
SOLVATION
STABLE ISOTOPES
400302* - Organic Chemistry- Isotope Effects- (-1987)