Heavy-atom kinetic isotope effects in the acid-catalyzed and thermal rearrangements of 2,2'-hydrazonaphthalene. Transition-state differences in their concerted rearrangements

1985 ◽  
Vol 107 (11) ◽  
pp. 3218-3223 ◽  
Author(s):  
Henry J. Shine ◽  
Ewa Gruszecka ◽  
Witold Subotkowski ◽  
Marilyn Brownawell ◽  
Joseph San Filippo
Keyword(s):  
Transition State ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Thermal Rearrangements ◽  
Acid Catalyzed

ChemInform Abstract: BENZIDINE REARRANGEMENTS. 18. MECHANISM OF THE ACID-CATALYZED DISPROPORTIONATION OF 4,4′-DIIODOHYDRAZOBENZENE. APPLICATION OF HEAVY-ATOM KINETIC ISOTOPE EFFECTS

1983 ◽  
Vol 14 (32) ◽  
Author(s):  
H. J. SHINE ◽  
J. HABDAS ◽  
H. KWART ◽  
M. BRECHBIEL ◽  
A. G. HORGAN ◽  
...  
Keyword(s):  
Isotope Effects ◽  
Heavy Atom ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Acid Catalyzed

Heavy Atom Kinetic Isotope Effects in HCN Elimination from Some Tricyanides in Methanol [1]

1978 ◽  
Vol 33 (12) ◽  
pp. 1496-1502
Author(s):  
Fouad M. Fouad ◽  
Patrick G. Farrell
Keyword(s):  
Transition State ◽  
Opposite Direction ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Transition States ◽  
Kinetic Isotope Effects ◽  
The Other ◽  
Kinetic Isotope ◽  
Solvent Isotope ◽  
Solvent Isotope Effects

AbstractRates of HCN elimination from polycyanides N,N-dimethyl-4-(1,2,2-tricyanoethyl)-aniline (1), 9-cyano-9-dicyanomethyl fluorene (2), 1,1-diphenyl-1,2,2-tricyanoethane (3), and 2-phenyl-1,1,2-tricyanopropane (4) have been studied in methanol. Elimination from 1 occurs via (E 1 c B)R, mechanism. On the other hand olefin formation from 2-4 has been shown to occur via (E 1)anion pathway. Heavy atom kinetic isotope effects indicated that product stability is not the sole factor controlling the transition state geometries. Values of k12/k14 were found to be in the order 2 > 3 > 4 > 1 which implied transition states with more carbanion-like structure in the opposite direction. Solvent isotope effects and enthalpies of activation were also determined and discussed in terms of transition states geometries.

Benzidine rearrangements. 18. Mechanism of the acid-catalyzed disproportionation of 4,4'-diiodohydrazobenzene. Application of heavy-atom kinetic isotope effects

1983 ◽  
Vol 105 (9) ◽  
pp. 2823-2827 ◽  
Author(s):  
Henry J. Shine ◽  
Jan Habdas ◽  
Harold Kwart ◽  
Martin Brechbiel ◽  
Ann Gafney Horgan ◽  
...  
Keyword(s):  
Isotope Effects ◽  
Heavy Atom ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Acid Catalyzed

Isotope effects in nucleophilic substitution reactions. III. The effect of changing the leaving group on transition state structure in SN2 reactions

1979 ◽  
Vol 57 (11) ◽  
pp. 1354-1367 ◽  
Author(s):  
Kenneth Charles Westaway ◽  
Syed Fasahat Ali
Keyword(s):  
Transition State ◽  
Nucleophilic Substitution ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Substituent Effects ◽  
Kinetic Isotope Effects ◽  
Substitution Reactions ◽  
Nucleophilic Substitution Reactions ◽  
Kinetic Isotope ◽  
Leaving Group

The nucleophilic substitution reactions of a series of 4-substituted phenylbenzyldimethyl-ammonium ions with thiophenoxide ions at 0 °C in N,N-dimethylformamide have been used to demonstrate how a change in the leaving group alters the structure of the SN2 transition state. Heavy atom (nitrogen) kinetic isotope effects, secondary α-deuterium kinetic isotope effects and Hammett ρ values provide qualitative descriptions of both the nucleophile–α-carbon and α-carbon–leaving group bonds in the transition states of these reactions. The results indicate that changing to a better leaving group causes the bond between the α-carbon and the nucleophile to be much more fully formed while the bond to the leaving group is essentially unchanged. The results are discussed in the light of current theories of substituent effects on SN2 reactions and a possible explanation for the surprising results (i) that the greatest effect is in the bond more remote from the point of structural change and (ii) that more nucleophilic assistance is required to displace a better leaving group is given.

Correction. Heavy-Atom Kinetic Isotope Effects in the Acid-Catalyzed Rearrangement of N-2-Napthyl-N'-phenylhydrazine. Rearrangement is Shown To Be a Concerted Process

1986 ◽  
Vol 108 (16) ◽  
pp. 5041-5041 ◽  
Author(s):  
Henry J. Shine ◽  
Lidia. Kupczyk-Subot-Kowska ◽  
Witold. Subotkowski
Keyword(s):  
Isotope Effects ◽  
Heavy Atom ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Acid Catalyzed

Heavy-atom kinetic isotope effects in the acid-catalyzed rearrangement of N-2-naphthyl-N'-phenylhydrazine. Rearrangement is shown to be a concerted process

1985 ◽  
Vol 107 (23) ◽  
pp. 6674-6678 ◽  
Author(s):  
Henry J. Shine ◽  
Lidia Kupczyk-Subotkowska ◽  
Witold Subotkowski
Keyword(s):  
Isotope Effects ◽  
Heavy Atom ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Acid Catalyzed
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