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 - 1991/5/1
Y1 - 1991/5/1
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 ρlg 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 ρlg 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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U2 - 10.1021/ja00010a037
DO - 10.1021/ja00010a037
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 -