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Alkylation, mechanism with benzyl chloride

A mechanism of this type permits substitution of certain aromatic and ahphatic nitro compounds by a variety of nucleophiles. These reactions were discovered as the result of efforts to explain the mechanistic basis for high-yield carbon alkylation of the 2-nitropropane anion by p-nitrobenzyl chloride. p-Nitrobenzyl bromide and iodide and benzyl halides that do not contain a nitro substituent give mainly the unstable oxygen alkylation product with this ambident anion ... [Pg.727]

The first clue to the existence of the SrnI mechanism came from product studies both in aliphatic and aromatic cases. It was noticed that in the reaction of benzyl and substituted benzyl chlorides with the 2-nitropropane anion, oxygen alkylation, yielding the oxime and then the aldehyde, occurs exclusively in the case of benzyl chloride and 3-nitrobenzyl chloride, whereas, with 4-nitrobenzyl chloride, the yield of aldehyde is only 6% and the carbon-alkylated (104) product is obtained in 92% yield (Kornblum, 1975). This was interpreted as the result of a competition between 8, 2 (O-alkylation) and S l (C-alkylation) reactions. In the aromatic case, it was observed that the reaction of 5- and 6-halopseudocumenes with KNHj in liquid ammonia (Kim and Bunnett, 1970) forms the 5- and 6-pseudocumi-dines in a ratio which is the same whether the starting compound is the 5- or 6-isomer in the case of the chloro- and bromo-derivatives, as expected from an aryne mechanism (Scheme 9), whereas much more non-rearranged... [Pg.75]

Kinetics and Mechanism of Reactions of Bis (methyl-2,2 -dimercaptodiethyl-amine) dinickel(II) with Alkyl Halides. The rates of reaction of [Ni2 CH3N-(CH2CH2S)2 2], structure III, with methyl iodide, benzyl bromide, benzyl chloride, p-chlorobenzyl chloride, and p-nitrobenzyl chloride have been studied as functions of temperature and concentration in chloroform (3). Absorbance measurements were utilized to determine the rates. All experiments were conducted with excess alkyl halide (20 to 1000 times the initial concentration of complex). Jicha and Busch (18) were able to isolate alkylated complexes of the composition... [Pg.138]

Alkyl halides with an electron-withdrawing group on the halogen-bearing carbon can be dimerized to alkenes by treatment with bases. The Z group may be nitro, aryl, and so on. It is likely that in most cases the mechanism involves nucleophilic substitution followed by elimination (illustrated for benzyl chloride) ... [Pg.1783]

The question arises why Fe -KlO catalyst has a special reactivity in this reaction. The activity pattern observed on the same series of catalyst samples for the alkylation of aromatics by benzyl chloride i.e. Fe -KlO > Zn -KlO > Cu -KlO KIO is compatible with the activities observed here, and suggests that the mechanism of formation of the carbocation could be similar, therefore occurs by oxidation. [Pg.86]

Benzo-15-crown-5 has been acetylated efficiently using KIO clays ion-exchanged by Cu, Fe or Zr. The best results were obtained with Fe -KlO. The catalytic properties are not related to the acidity of the solid and it can therefore be admitted that the C-Cl bond is activated by a redox mechanism, as proposed earlier for the alkylation of aromatic compounds by benzyl chloride. [Pg.88]

Bibenzyl is formed in a yield of 22% when a degassed solution in acetonitrile of benzyl chloride, an electron donor such as triethylamine and a catalytic amount of the gold complex 88, is irradiated. The gold complex (88) is described as a potent new photocatalyst for such systems and performs better than existing catalysts. The mechanism of the process has been shown to involve direct halogen transfer as shown in equation 9. The resultant alkyl radicals then yield the final product. A similar reaction operates with 1-bromopentane when it is irradiated under the same conditions This yields -decane178. [Pg.381]


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See also in sourсe #XX -- [ Pg.121 ]




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Alkyl chloride alkylation

Alkyl chlorides

Alkylation mechanism

Alkyls benzyls

Benzyl chloride

Benzyl chloride, alkylation

Benzylic chlorides

Mechanisms alkylations

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