In the previous post, we saw that a benzene ring with an activator undergoes electrophilic aromatic substitution at the ortho and para positions, while deactivated aromatic rings react at the meta position: Here is an interesting question: Where … Read more
Halogens are ortho, para directors, however, they are also deactivators! Here is short summary to answer why halogens, being deactivators, are still ortho, para directors: Now, let’s discuss this a bit more in detail by first doing a … Read more
Aryl diazonium salts can be used as an alternative to the standard electrophilic aromatic substitution reactions for preparing aromatic compounds as well as for synthesizing compounds that cannot be prepared directly from benzene. Before going into the details, here is the summary … Read more
In the previous post, we talked about the orientation effects in EAS when there is more than one substituent on the benzene ring. In short, to predict the substitution site, you need to determine the stronger activator. Using … Read more
In this article, we will discuss the main limitations and undesired pathways in electrophilic aromatic substitution reactions and the strategies to overcome them. Friedel-Crafts Reactions The Friedel-Crafts reactions are used for alkylation and acylation of aromatic compounds. Rearrangement … Read more
In this post, we will talk about the ortho-, meta, and para directors in electrophilic aromatic substitution (EAS). As a reminder, the ortho-, meta, and para are the relative positions of the two groups in a disubstituted aromatic ring: … Read more
We have seen, in the Friedel-Crafts alkylation reaction, that rearrangements do not allow for the preparation of primary alkyl benzenes: To overcome this limitation, you can first prepare the corresponding aryl ketone by the Friedel-Crafts acylation and then … Read more
In the previous post, we learned about the Friedel–Crafts alkylation and discussed its mechanism and limitations. In Friedel–Crafts acylation, aromatic compounds are reacted with an acyl halide to prepare an aryl ketone: The electrophile in this reaction is … Read more
In the previous post, we learned about the electrophilic aromatic substitution reactions and went over the mechanisms of halogenation, nitration, and sulfonation of the benzene ring. Following an identical mechanism, two reactions, discovered by Charles Friedel and James Crafts in … Read more
Benzene has 3 π bonds and, as expected, shows some similarities to alkenes in being reactive towards electrophilic species. However, there are two key differences between their reactions with electrophiles. First, benzene is very stable and thus less reactive. Second, unlike … Read more
