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Kinetic studies on the aminolysis of 1‐(trimethylsilyl)ethyl arenesulphonates in acetonitrile and methanol
Author(s) -
Oh Hyuck Keun,
Shin Chul Ho,
Park Hyoung Yeon,
Lee Ikchoon
Publication year - 1994
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/poc.610070705
Subject(s) - chemistry , aminolysis , nucleophile , substituent , acetonitrile , trimethylsilyl , methanol , medicinal chemistry , nucleophilic substitution , leaving group , reaction rate constant , stereochemistry , organic chemistry , kinetics , catalysis , physics , quantum mechanics
Nucleophilic substitution reactions of 1‐(trimethylsilyl)ethyl arenesulphonates with anilines and benzylamines in acetonitrile and methanol at 65·0°C were studied. The cross‐interaction constants, ρXZ, between substituents in the nucleophile (X) and leaving group (Z) are relatively small (0·10 for XC 6 H 4 NH 2 in MeCN) but similar to those for other S N 2 processes at a secondary carbon atom. This provides further evidence for an approximately constant, loose S N 2 transition state at a secondary carbon regardless of the size of the C α substituent. The transition‐state variations with substituents X and Z are in accord with that expected from the positive ρXZ value observed: a stronger nucleophile and/or nucleofuge leads to an earlier transition state, i.e. a lower degree of bond making and breaking.