Nucleophilic addition to olefins. 5. Reaction of 1,1-dinitro-2,2-diphenylethylene with water and hydroxide ion in 50% Me/sub 2/SO-50% water. Complete kinetic analysis of hydrolytic cleavage of the C=C double bond in acidic and basic solution

Journal Article · Wed Aug 12 04:00:00 EDT 1981 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00406a030· OSTI ID:6127480

Bernasconi, C F; Carre, D J; Kanavarioti, A

Hydrolysis of 1,1-dinitro-2,2-diphenylethylene (2) to form benzophenone and dinitromethane (or its anion) was studied in 50% Me/sub 2/SO-50% H/sub 2/O and also in 50% Me/sub 2/SO-50% D/sub 2/O at pHs of 1 to 16. Solvent isotope effects general acid and general base catalysis, and structure-reactivity relationships were used to study the kinetics. The conclusions are the following: (1) the equilibrium constants for OH/sup -/ and water addition to 2 to form T/sub OH//sup -/ are comparable to those for the corresponding reactions of benzylidene Meldrum's acid (1), but the rate constants are much lower for 2 than for 1; (2) carbon protonation of T/sub OH//sup -/ follows an Eigen curve similar to that for 1,1-dinitroethane anion but which is displaced upward by nearly 1 log unit. This indicates a higher intrinsic protonation rate because of a smaller charge delocalization in T/sub OH//sup -/ owing to an enhanced steric hindrance to coplanarity of the nitro groups in T/sub OH//sup -/; (3) intramolecular proton transfer from the OH group to the carbanionic site in T/sub OH//sup -/ is insignificant, which is in contrast to the behavior of the addition complex between 2 and morpholine; (4) the base-catalyzed breakdown of T/sub OH//sup 0/ into benzophenone and dinitromethane anion occurs by rate-limiting oxygen deprotonation, which implies that k/sub 4/ for CH(NO/sub 2/)/sub 2//sup -/ departure from T/sub OH//sup 0 -/ is much greater than 2 x 10/sup 9/ s/sup -1/, a remarkably high rate for a carbanionic leaving group. The water-catalyzed breakdown of T/sub OH//sup 0/ proceeds by a different mechanism, which is most likely concerted, with a transition state; (5) the acid-catalyzed breakdown of T/sub OH//sup 2 -/ occurs by rate-limiting carbon protonation (k/sub 6//sup BH/), but the water-catalyzed breakdown follows a different mechanism. Various possibilities are discussed, and a slight preference is given to a preassociation mechanism.

• Research Organization: Univ. of California, Santa Cruz
• OSTI ID: 6127480
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 103:16; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400302* -- Organic Chemistry-- Isotope Effects-- (-1987)
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
DEUTERIUM
EXPERIMENTAL DATA
HEAVY WATER
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROLYSIS
INFORMATION
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LIGHT NUCLEI
LYSIS
NITRO COMPOUNDS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
REACTION KINETICS
SOLVOLYSIS
STABLE ISOTOPES
WATER