Stereochemistry Exercise 4

by James

Enantiomers, diastereomers, or the same?

 

{ 3 comments… read them below or add one }

Eric October 11, 2013 at 12:49 pm

In the previous videos on stereochemistry you stated when you have a dash in the 4th order group such as hydrogen you assume the rotation is the opposite after you order the other groups, so R becomes S because a clockwise changes to counter clockwise. In this video you did bond rotations by swapping out three of the bonds. My question is why did you have to do that in these compounds, but did not for the dashed hydrogen stereocenters in the previous video?

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Eric October 11, 2013 at 12:50 pm

sorry I meant “wedge” for hydrogen 4th group, not dash…

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James October 18, 2013 at 1:48 pm

I did the rotation here because the #4 priority group was in the plane of the page. It’s a choice – one could either do a bond rotation, or swap two groups and then remember to “flip” the R/S designation one gets. Rotation seemed to me to be the easiest thing to visualize here. I hope it was clear.

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