EK Ochem (page 61)

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

supras2kracer

Full Member
10+ Year Member
5+ Year Member
15+ Year Member
Joined
Jan 20, 2007
Messages
72
Reaction score
0
This is page 61 of the EK Ochem lecture book.

I think the books is wrong (or just very poorly written) but I wanted to make sure with other people. The paragraph says:

The electron withdrawing carbonyl group pulls electrons from the carbon-carbon double bond and makes the beta carbon less susceptible to attack by a nucleophile (electrophilic addition). Thus, rather than the nucleophile adding to the beta carbon it may sometime add to the oxygen atom, forming the enol-keto tautomers.

This picture is what they have directly below the paragraph but the nucleophile doesn't add to the oxygen.


ek.jpg

The next picture (I didn't feel like taking 10 minutes to draw it) comes after a paragraph that says that the nucleophile also adds to the alpha carbon often. Except the reaction picture that follows doesn't show this. It just shows what happens if you add the nucleophile first, then the electrophile (H+). Picture still shows the nucleophile being added to the beta carbon.

Members don't see this ad.
 
This is page 61 of the EK Ochem lecture book.
I think the books is wrong (or just very poorly written) but I wanted to make sure with other people. The paragraph says:

The electron withdrawing carbonyl group pulls electrons from the carbon-carbon double bond and makes the beta carbon less susceptible to attack by a nucleophile (electrophilic addition). Thus, rather than the nucleophile adding to the beta carbon it may sometime add to the oxygen atom, forming the enol-keto tautomers.
This is total nonsense. That this got through throws up a bright red flag about the quality of the whole book.

This picture is what they have directly below the paragraph but the nucleophile doesn't add to the oxygen.


ek.jpg

Are you sure? I see it directly under the paragraph about conjugate addition. That paragraph and the above picture go together and are true.

The next picture (I didn't feel like taking 10 minutes to draw it) comes after a paragraph that says that the nucleophile also adds to the alpha carbon often. Except the reaction picture that follows doesn't show this. It just shows what happens if you add the nucleophile first, then the electrophile (H+). Picture still shows the nucleophile being added to the beta carbon.

Yes, that picture does not fit with the paragraph above it. It's just a slightly different mechanism for conjugate addition.

In general, the quality of the review book is much lower than that of textbooks. Be skeptical when reading it, and if something smells bad, there just might be a dead fish in there.
 
Well the thing directly above the photo is just one sentence. I didn't think they'd draw up a big set of diagrams for one or two sentences.

What do you mean when you say that it's total nonsense?
Is it completely wrong? So the carbonyl pulls electrons away from the beta carbon making it even more partial positive. Nucleophiles attack partial positives so it should attack the beta carbon way more often than oxygen, right?

I've kind of figured out the quality of these books after having to come here every day to clear up ambiguities and possible mistakes. How do the EK books get such good reviews? It puts a lot of stuff into the simplest terms possible, which I like, but it's not necessarily a good thing if you don't already have somewhat of an idea what they're talking about.
 
Well the thing directly above the photo is just one sentence. I didn't think they'd draw up a big set of diagrams for one or two sentences.

What do you mean when you say that it's total nonsense?
Is it completely wrong? So the carbonyl pulls electrons away from the beta carbon making it even more partial positive. Nucleophiles attack partial positives so it should attack the beta carbon way more often than oxygen, right?

I've kind of figured out the quality of these books after having to come here every day to clear up ambiguities and possible mistakes. How do the EK books get such good reviews? It puts a lot of stuff into the simplest terms possible, which I like, but it's not necessarily a good thing if you don't already have somewhat of an idea what they're talking about.

Yup
 
Members don't see this ad :)
Well the thing directly above the photo is just one sentence. I didn't think they'd draw up a big set of diagrams for one or two sentences.

What do you mean when you say that it's total nonsense?
Is it completely wrong? So the carbonyl pulls electrons away from the beta carbon making it even more partial positive. Nucleophiles attack partial positives so it should attack the beta carbon way more often than oxygen, right?

I've kind of figured out the quality of these books after having to come here every day to clear up ambiguities and possible mistakes. How do the EK books get such good reviews? It puts a lot of stuff into the simplest terms possible, which I like, but it's not necessarily a good thing if you don't already have somewhat of an idea what they're talking about.

Nucleophiles will never attack the oxygen.
 
The above posters are correct and this is probably what I think they meant. When they use "it", they actually mean the acidic proton (H+) in the solution added to the oxygen atom. Hence, the prase "attack by a nucleophile (electrophilic addition). " is ambiguous here. For what is worth, you can read more on "the enol-keto tautomers" to have a better understanding of this rxn. However, I do agree with you that the passage wordings is very confusing.
 
Last edited:
Top