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### Topic: How to find the R/S configuration of these carbons?  (Read 1839 times)

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#### sharbeldam

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##### How to find the R/S configuration of these carbons?
« on: May 10, 2019, 04:53:40 PM »

Is it true that atoms pointing upwards are always wedged? so if i look at the right carbon it should be R but since the hydrogen is wedged, it is S? that's the way to do it?

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#### sharbeldam

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##### Re: How to find the R/S configuration of these carbons?
« Reply #1 on: May 10, 2019, 11:21:00 PM »
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#### AWK

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##### Re: How to find the R/S configuration of these carbons?
« Reply #2 on: May 11, 2019, 02:46:48 AM »
Both carbon atoms show the same configuration
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#### sharbeldam

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##### Re: How to find the R/S configuration of these carbons?
« Reply #3 on: May 11, 2019, 02:49:01 AM »
Thank you AWK, but can you tell me if the way i did it is true? i can consider the upward atoms wedged? always?
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#### AWK

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##### Re: How to find the R/S configuration of these carbons?
« Reply #4 on: May 11, 2019, 03:29:30 AM »
You can change the surrounding of carbon atom into a spatial view or typical Fischer view. For both cases, rules exist that allow you to assign the proper configuration unambiguously.
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#### sharbeldam

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##### Re: How to find the R/S configuration of these carbons?
« Reply #5 on: May 11, 2019, 03:36:35 AM »
to simplify this question, without changing the view of this molecule, can i consider this molecule ins the picture haworth projection which means that any upward atom is wedged and figure out the configuration simply by doing that?

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#### AWK

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##### Re: How to find the R/S configuration of these carbons?
« Reply #6 on: May 11, 2019, 03:44:39 AM »
Rules for configuration in Haworth projection works correctly for normal sugars only. They do not work for deoxysugars, for example.
You should show you attempt, according to Forum rules.
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#### sharbeldam

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##### Re: How to find the R/S configuration of these carbons?
« Reply #7 on: May 11, 2019, 04:02:37 AM »
I'm really sorry If I seem dense.
So since I cant consider this molecule a haworth projection, may I ask and if i get this question in the exam to figure out if the carbon is R or S. can you show me simple steps how can you tell if it's clockwise or counterclockwise? knowing that the 4th priority need to be going inside (Dashed)

I'd really appreciate it, thank you
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#### AWK

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##### Re: How to find the R/S configuration of these carbons?
« Reply #8 on: May 11, 2019, 04:26:40 AM »
First of all, rotate your picture by 180 degrees around the axis perpendicular to the plane of your picture. You can see that the configuration of both carbon atom is the same.
Then assign priorities for, eg left carbon atom - Cl>CHCl>CH2>H. Now turn the carbon atom with its substituents so that the hydrogen atom is behind the carbon atom. Then look only at the priority of the three substituents over the carbon atom - if they are arranged clockwise - the configuration is R; if on the contrary - S.
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#### sharbeldam

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##### Re: How to find the R/S configuration of these carbons?
« Reply #9 on: May 11, 2019, 06:07:59 AM »
Thanks alot.
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#### hollytara

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##### Re: How to find the R/S configuration of these carbons?
« Reply #10 on: May 14, 2019, 12:22:52 AM »