Determining R/S on a Fischer Projection

by James

 

{ 7 comments… read them below or add one }

M. Sankombo

thank you soo much. this has been extremely helpful

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E Blake

Hi! Can you please explain, if there is a longer chain, eg 3 stereocentres, how do you know for the middle stereocentre how to draw it in 3d? Which way is ‘up’ (flat on the page) and which way would be ‘down) (ie going behind us)

Hope that makes sense, thanks!

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james

Always for a Fischer, the groups pointing on the side are coming out of the page. That’s all the information you need to figure out R/S. As far as drawing in 3D, if you have that information, it’s probably best to redraw the molecule in “zigzag” formation and then use the R/S information to draw in the stereocenters that way.

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Ray

If the highest priority substituent is going into the page(dashed line) do you flip from R to S/vice versa?

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Shori

MY SAVIOR!! Thanks so much for doing this!

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Brian

I think you made a mistake naming the carbons. Around the 8 minute mark, you said the two stereocenters were on C1 and C2 when they are actually on C2 and C3.

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Jake

Exactly the video I needed. Thanks again! :)

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