Premium
The Menschutkin reaction of benzyl p ‐toluenesulfonates with N,N ‐dimethylanilines. Evidence for the duality of S N 1 and S N 2 mechanisms
Author(s) -
Kim Sung Hong,
Yoh SooDong,
Lim Chultack,
Mishima Masaaki,
Fujio Mizue,
Tsuno Yuho
Publication year - 1998
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199804)11:4<254::aid-poc2>3.0.co;2-6
Subject(s) - chemistry , sn2 reaction , substituent , reaction rate constant , nucleophile , acetonitrile , medicinal chemistry , computational chemistry , stereochemistry , kinetics , organic chemistry , catalysis , quantum mechanics , physics
The rate data for the Menschutkin reaction between strongly activated Z‐substituted benzyl p ‐toluenesulfonates and Y‐substituted N,N ‐dimethylanilines in acetonitrile at 35 °C fit the equation, k obs = k 1 + k 2 [DMA], which is consistent with concurrent first‐ and second‐order processes. The k 1 and k 2 values for each substrate were separated based on the above equation. The S N 1 rate constant, k 1 , is unaffected by the nature of the nucleophile, whereas the S N 2 rate constant, k 2 , increased with the electron‐donating substituent of the N,N ‐dimethylaniline. The substituent effect on the k 1 values is linearly correlated by the Yukawa–Tsuno equation with ρ = −5.2 and r = 1.3. The unimolecular reaction can be regarded as a classical S N 1 mechanism. In contrast, that on the k 2 values shows an upward curvature when analyzed by the Brown σ + treatment. These results are ascribed to the simultaneous and independent occurrence of S N 1 and S N 2 mechanisms in the present Menschutkin reaction. © 1998 John Wiley & Sons, Ltd.