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The ‘dimer mechanism’ in aromatic nucleophilic substitution by amines in aprotic solvents
Author(s) -
Nudelman Norma S.
Publication year - 1989
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.610020102
Subject(s) - chemistry , nucleophile , dimer , amine gas treating , nucleophilic substitution , hydrogen bond , mechanism (biology) , nucleophilic aromatic substitution , acceptor , computational chemistry , catalysis , photochemistry , medicinal chemistry , organic chemistry , molecule , philosophy , physics , epistemology , condensed matter physics
The mechanism of aromatic nucleophilic substitutions by amines in protic solvents is well established; on the contrary the mechanism/s of the reactions in aprotic solvents is/are still subject of controversy. The present paper describes several systems for which fourth‐order kinetics (third‐order in amine) were observed. A mechanism is proposed to account for this as well as other observation such as: overall negative energies of activation, quadratic dependence of k A with non‐nucleophilic tertiary bases, spectacular effects of hydrogen‐bond donor (HBD) and hydrogen‐bond acceptor (HBA) catalysts, etc. Other alternative mechanisms are also discussed.