Abstract
Elimination reactions of N-(arylsulfonoxy)-N-alkylbenzylamines 1-5 with MeONa-MeOH have been studied kinetically. The elimination reactions are regiospecific, producing only corresponding benzylidenalkylamines. The rate equation for the reactions is kobs = k0 + k2[MeONa], indicating that the reactions proceed by competing solvolytic- and base-promoted pathways. The relative rates of elimination for the k2 and k0 pathways are 1, 0.67, 0.53, 0.35, and 0.27 for R = Me, Et, i-Pr, s-Bu, and t-Bu and 1, 4.1, 5.1, and 8.7 for R = Et, i-Pr, s-Bu, and t-Bu, respectively. For MeONa-promoted elimination from 1-5, Hammett ρ and kH/kD decrease but ρ1g and |β1g| increase with a bulkier alkyl substituent. However, the values for the solvolytic eliminations are nearly the same for all substrates and are similar to those for the base-promoted pathway, except for the ρ values, which have opposite signs. From these results, the changes in transition-state structure wrought by variation of N-alkyl substituents are assessed.
| Original language | English |
|---|---|
| Pages (from-to) | 3920-3924 |
| Number of pages | 5 |
| Journal | Journal of the American Chemical Society |
| Volume | 113 |
| Issue number | 10 |
| Publication status | Published - 1991 May 8 |
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Reactions of N-(arylsulfonoxy)-N-alkylbenzylamines with MeONa-MeOH. Steric effect on the structure of the imine-forming transition state. / Cho, Bong-Rae; Pyun, Sang Yong.
In: Journal of the American Chemical Society, Vol. 113, No. 10, 08.05.1991, p. 3920-3924.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Reactions of N-(arylsulfonoxy)-N-alkylbenzylamines with MeONa-MeOH. Steric effect on the structure of the imine-forming transition state
AU - Cho, Bong-Rae
AU - Pyun, Sang Yong
PY - 1991/5/8
Y1 - 1991/5/8
N2 - Elimination reactions of N-(arylsulfonoxy)-N-alkylbenzylamines 1-5 with MeONa-MeOH have been studied kinetically. The elimination reactions are regiospecific, producing only corresponding benzylidenalkylamines. The rate equation for the reactions is kobs = k0 + k2[MeONa], indicating that the reactions proceed by competing solvolytic- and base-promoted pathways. The relative rates of elimination for the k2 and k0 pathways are 1, 0.67, 0.53, 0.35, and 0.27 for R = Me, Et, i-Pr, s-Bu, and t-Bu and 1, 4.1, 5.1, and 8.7 for R = Et, i-Pr, s-Bu, and t-Bu, respectively. For MeONa-promoted elimination from 1-5, Hammett ρ and kH/kD decrease but ρ1g and |β1g| increase with a bulkier alkyl substituent. However, the values for the solvolytic eliminations are nearly the same for all substrates and are similar to those for the base-promoted pathway, except for the ρ values, which have opposite signs. From these results, the changes in transition-state structure wrought by variation of N-alkyl substituents are assessed.
AB - Elimination reactions of N-(arylsulfonoxy)-N-alkylbenzylamines 1-5 with MeONa-MeOH have been studied kinetically. The elimination reactions are regiospecific, producing only corresponding benzylidenalkylamines. The rate equation for the reactions is kobs = k0 + k2[MeONa], indicating that the reactions proceed by competing solvolytic- and base-promoted pathways. The relative rates of elimination for the k2 and k0 pathways are 1, 0.67, 0.53, 0.35, and 0.27 for R = Me, Et, i-Pr, s-Bu, and t-Bu and 1, 4.1, 5.1, and 8.7 for R = Et, i-Pr, s-Bu, and t-Bu, respectively. For MeONa-promoted elimination from 1-5, Hammett ρ and kH/kD decrease but ρ1g and |β1g| increase with a bulkier alkyl substituent. However, the values for the solvolytic eliminations are nearly the same for all substrates and are similar to those for the base-promoted pathway, except for the ρ values, which have opposite signs. From these results, the changes in transition-state structure wrought by variation of N-alkyl substituents are assessed.
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UR - http://www.scopus.com/inward/citedby.url?scp=0001440908&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0001440908
VL - 113
SP - 3920
EP - 3924
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 10
ER -