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ChemicalBook >> journal list >> Journal of The Chemical Society-perkin Transactions 1 >>article

Kinetics and mechanism of the addition of triphenylphosphoniocyclopentadienide to tetrachloro-p-benzoquinone

Published:1 January 1991 DOI: 10.1039/P29910001925
F. P. Plá,?J. Palou,?R. Valero,?C. Hall,?P. Speers

Abstract

The kinetics and mechanism of the reaction of triphenylphosphoniocyclopentadienide 1 with tetrachloro-p-benzoquinone (chloranil 2a) to yield 2,3,5-trichloro-6-(3-triphenylphosphoranylidene-cyclopenta-1,4-dienyl)-p-benzoquinone 3 in dichloromethane solution are reported. The rate limiting step was found to be electrophilic attack of tetrachloro-p-benzoquinone on the aromatic cyclopentadiene ring of the ylide. A thermochemical study of the system showed a small enthalpy and a large negative entropy of activation in agreement with the existence of a highly polar betaine as ah intermediate in the reaction. The proposed mechanism involves bimolecular transfer of a proton to a molecule of ylide. No evidence was found either for the formation of a π-complex or for acid catalysis of the reaction.

Substances (3)

Related products
Procduct Name CAS Molecular Formula Supplier Price
Dichloromethane 75-09-2 CH2Cl2 1289 suppliers $8660.00
Chloranil 118-75-2 C6Cl4O2 566 suppliers $10.00-$4094.90
(TRIPHENYLPHOSPHONIO)CYCLOPENTADIENIDE C23H19P - Inquiry

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