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junior college 2 | H3 Maths
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Sorry there isnt any option for chemistry. But may i know what is wrong? What are the steps in thinking process for this question?
Date Posted: 3 years ago
Views: 336
You will need to draw the chair confirmation out first.
Those bonds with dashed lines or longer dashes (∥∥∥∥∥∥) are 'down'
Those with wedges are 'up'
From here, you then decide if it's equatorial or axial
Those bonds with dashed lines or longer dashes (∥∥∥∥∥∥) are 'down'
Those with wedges are 'up'
From here, you then decide if it's equatorial or axial
I will see if I can provide a drawing later
Thanks alot, picture will help me as I tried to do that but cant seem to get the answer especially for second structure. Am i supposed to take note of the bulky group and put it on equatorial position?
Yes, good observation there.
Actually hold on.
From the looks of the second structure, it's probably the case that the bulkier group and the OH group should not be co-equatorial to minimise steric hindrance/interactions.
From the looks of the second structure, it's probably the case that the bulkier group and the OH group should not be co-equatorial to minimise steric hindrance/interactions.
Means have to change their axial and equatorial position?
Oops. Rather, the OH and bulky group are adjacent to each other, and both are 'down', so it is not possible to have both equatorial or both axial.
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Left molecule. The orientation is shown differently but the order is correct.
Date Posted:
3 years ago
For the picture, you may not be able to see the full thing on the app. You'll need to 'pinch' it in to zoom out
Right molecule will be uploaded later.
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For the molecule on the right.
Date Posted:
3 years ago
Thank you very much for the pictures! But would like to just clarify, why isn't there any diaxial interaction for the first structure? Isnt it 1,3 diaxial interaction? So since CH(CH3)2 is in axial, can it have diaxial interaction with the Hydrogen at the third carbon?
I wrote :
'There are no diaxial interactions between it and the equatorial OH and CH3 groups'
The 'it' here refers to the bulky group.
This doesn't mean that the bulky group has no diaxial interactions with the axial Hs.
'There are no diaxial interactions between it and the equatorial OH and CH3 groups'
The 'it' here refers to the bulky group.
This doesn't mean that the bulky group has no diaxial interactions with the axial Hs.
For the configuration on top, you have 1 bulky group having 1,3-diaxial interactions with 2 axial Hs.
For the configuration below, you have 1 OH and 1 CH3 group having 1,3-diaxial interactions with 1 axial H, as well as with each other.
OH and CH3 are both bigger substituents than a single H (hydrogen is the smallest atom in the entire Periodic table).
So the combined interactions (i.e steric) between the OH,CH3 and axial H will be bigger and outweigh the interactions between bulky group and two small Hs.
For the configuration below, you have 1 OH and 1 CH3 group having 1,3-diaxial interactions with 1 axial H, as well as with each other.
OH and CH3 are both bigger substituents than a single H (hydrogen is the smallest atom in the entire Periodic table).
So the combined interactions (i.e steric) between the OH,CH3 and axial H will be bigger and outweigh the interactions between bulky group and two small Hs.
Ohh yes! Finally understand now. Thank you very much!!
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