- Tautomer-selective derivatives of enolate, ketone and enaminone by addition reaction of picolyl-type anions with nitriles
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We describe an efficient for the synthesis of compounds of tautomeric β-pyridyl/quinolyl-enol, -ketone, -enaminone, which were finally characterized by standard methods like NMR, IR or SCXRD. The addition reaction of lithiated intermediates of picoline, 2-ethylpyridine and 2-methylquinoline, respectively, with nitriles followed by acid hydrolysis afforded the corresponding tautomeric compounds of enol, ketone and emaminone. Interestingly, treatment of 2-methylpyridine or 2-ethylpyridine with nitriles, respectively, yielded mostly β-pyridyl ketone and enol tautomers without enaminones, while 2-methylquinoline with nitriles gave β-quinolyl ketone and enaminone tautomers without enols. The reaction of 2-benzylpyridine with nitriles was not available under the same conditions.
- Bai, Jianliang,Wang, Peng,Cao, Wei,Chen, Xia
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p. 645 - 652
(2016/09/28)
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- Catalysis by Ferrous Ion in Nucleophilic Aromatic Substitution Reactions
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Efficient catalysis is provided by ferrous chloride in the nucleophilic aromatic substitution reaction of several aryl and heteroaryl halides with a ketone enolate ion as the nucleophile in Me2SO, to give the aryl or heteroaryl ketones in fair to good yields.The enolate ions from pinacolone, acetophenone, cyclohexanone and pentan-3-one behave successfully.A side-reaction is represented in some cases by the hydrodehalogenation of the substrate ArX, and evidence is provided for the intermediacy of both Ar(radical) and Ar(anion) species.Other significant mechanistic clues acquired include: (i) inhibition by electron and radical scavengers; (ii) entrainment of poor nucleophiles by good ones; (iii) the relative reactivity of two nucleophiles in competition experiments with Phl under Fe2+ catalysis having the same value as in the experiments under both photostimulation and spontaneous initiation.All these findings are consistent with an SRN1 mechanism of substitution where ferrous ion, in combination with the nucleophile, plays an important role in the initiation step.
- Galli, Carlo,Gentili, Patrizia
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p. 1135 - 1140
(2007/10/02)
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- THE RELATIVE REACTIVITY OF SUBSTRATE IN SRN1 REACTIONS
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The factors affecting the relative reactivity of aryl halides in SRN1 aromatic nucleophilic substitutions are analyzed and compared.Competition experiments of pairs of substrates, in photostimulated reaction with pinacolone enolate ion in liqui
- Galli, Carlo
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p. 365 - 368
(2007/10/02)
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