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Effect of Anchimeric Assistance in the Reaction of Triphenylphosphine with α,β‐Unsaturated Carboxylic Acids
Author(s) -
Salin Alexey V.,
Fatkhutdinov Albert R.,
Il'in Anton V.,
Galkin Vladimir I.
Publication year - 2014
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20842
Subject(s) - chemistry , steric effects , intramolecular force , phosphonium , triphenylphosphine , zwitterion , phosphine , medicinal chemistry , maleic acid , hydrogen atom , hydrogen bond , carboxylic acid , photochemistry , electronic effect , stereochemistry , polymer chemistry , organic chemistry , molecule , catalysis , group (periodic table) , polymer , copolymer
Quaternization of triphenylphosphine with maleic and cis ‐aconitic acids is strongly accelerated by participation of the cis ‐carboxyl group in stabilization of the phosphonium zwitterion intermediate by intramolecular hydrogen bonding, in spite of steric hindrance by the acid's reaction center. A similar effect for trans ‐isomeric acids is not observed, which can be rationalized on the basis of spatial structures of the generated zwitterions, implying an electrostatic interaction between the phosphonium center and carbonyl oxygen atom. The effect of anchimeric assistance decreases when the intramolecular hydrogen bonding disfavors attack of the phosphine on the sterically less hindered carbon atom of the C=C bond, as observed for cis ‐aconitic acid.