作业帮有机化学中的“傅克反应”的机理是什么?要英文版的!
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有机化学中的“傅克反应”的机理是什么?要英文版的!
有机化学中的“傅克反应”的机理是什么?要英文版的!
有机化学中的“傅克反应”的机理是什么?要英文版的!
The Friedel-Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877.There are two main types of Friedel-Crafts reactions:alkylation reactions and acylation reactions.This reaction type is part of electrophilic aromatic substitution.
A:Friedel-Crafts alkylation involves the alkylation of an aromatic ring and an alkyl halide using a strong Lewis acid catalyst.With anhydrous ferric chloride as a catalyst,the alkyl group attaches at the former site of the chloride ion.
B:Friedel-Crafts acylation is the acylation of aromatic rings with an acyl chloride using a strong Lewis acid catalyst.Friedel-Crafts acylation is also possible with acid anhydrides.Reaction conditions are similar to the Friedel-Crafts alkylation.This reaction has several advantages over the alkylation reaction.Due to the electron-withdrawing effect of the carbonyl group,the ketone product is always less reactive than the original molecule,so multiple acylations do not occur.Also,there are no carbocation rearrangements,as the carbonium ion is stabilized by a resonance structure in which the positive charge is on the oxygen.