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wearelulu 2013-5-10 01:22 PM

alkylation problem

Friedel–Crafts Alkylation has a limitation on working a deactivating substituted benzene ring. Are there any explanations?



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jmlo 2013-5-10 10:31 PM

回覆 1# 的帖子

Yes. Friedal-Craft alkylation prefers an activated benzene.

wearelulu 2013-5-11 09:48 AM

[quote]原帖由 [i]jmlo[/i] 於 2013-5-10 10:31 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=361084279&ptid=21885645][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
Yes. Friedal-Craft alkylation prefers an activated benzene. [/quote]
Any reasons behind?



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jmlo 2013-5-11 10:22 AM

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Alkylation on benzene ring is an electrophilic aromatic substitution. To speed up the reaction, either the carbocation has to be stabilized (e.g. by using AlCl3) or the benzene ring be activated (e.g. by introducing activating groups such as NH2, R, OR) which enhance the ring electron density, making it more nucleophilic.
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