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junior college 1 | H3 Maths
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Pauline
Pauline

junior college 1 chevron_right H3 Maths chevron_right Singapore

My answer will be Compound A. However i am not sure if Compound B will be the correct answer instead?

Date Posted: 2 years ago
Views: 586
J
J
2 years ago
B. The nucleophile attacks from the opposite side of the leaving group.

There is an inversion of configuration.
J
J
2 years ago
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Book%3A_Organic_Chemistry_with_a_Biological_Emphasis_v2.0_(Soderberg)/09%3A_Phosphate_Transfer_Reactions/9.03%3A_Phosphate_Transfer_Reactions_-_An_Overview

Refer to the energy diagram for the pentavalent transition state
Pauline
Pauline
2 years ago
Thank you! Actually i have another question. Could u please help me if i post it under answers?
J
J
2 years ago
Got to see the question first
Pauline
Pauline
2 years ago
I added the question together with my answer. My approach to the question is stated in the answers but not too sure if my way of thinking is correct?

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Pauline
Pauline's answer
5 answers (A Helpful Person)
1st
Is my concept correct here? Ketone is meta directing hence is 1,3. So i count from the carbon nearest to ketone (the circled carbon) to the third carbon. There can be two possibilities. However the one on top cannot be the answer due to steric hindrance. Am i correct?
J
J
2 years ago
Both are possible.

The ketone attached to C1 is meta-directing (1,3 relative to this carbon)

The alkyl group next to it on C2 is ortho-para directing (2,4 relative to this carbon)

Both directing groups are in sync and don't conflict. So you'll expect the SO3H to be added to be added to C3 or C5.

The steric hindrance just means that addition to C3 will be the minor product and to C5 will be the major product. (In some percentages)

It isn't necessarily all or nothing.
Pauline
Pauline
2 years ago
Thank you for the reply! I added a new picture under answers i hope i understood your explanations correctly?
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Pauline
Pauline's answer
5 answers (A Helpful Person)
Is this what u mean? So this should be the right answer?
J
J
2 years ago
Yes.
Pauline
Pauline
2 years ago
Ahh i see! Okay thank so much for your help!!! I really appreciate it!!
J
J
2 years ago
Even for basic electrophilic addition of something like Cl to methylbenzene (toluene) you'll usually see the para addition to be the major product and ortho addition to be the minor product, despite very small steric hindrance.


https://www.masterorganicchemistry.com/2018/01/29/ortho-para-and-meta-directors-in-electrophilic-aromatic-substitution/
Pauline
Pauline
2 years ago
Ok sure will check out the link! Thank you very much!