Fischer Projection question

[onedirection]

---

Members don't see this ad.

My notes just have two contradicting things I think

just wanted to confirm which was true

In a Fischer's Projection, be aware that a H on the left/right side can change the absolute configuration; ie you flip the S/R if there's a H on the coming out of the page/on the left/right side of the carbon

But elsewhere I have written "In a Fisch'ers projection, you don't flip the rotation if H is on the left/right"

which one is correct?

 

[FeinMS]

My notes just have two contradicting things I think

just wanted to confirm which was true

In a Fischer's Projection, be aware that a H on the left/right side can change the absolute configuration; ie you flip the S/R if there's a H on the coming out of the page/on the left/right side of the carbon

But elsewhere I have written "In a Fisch'ers projection, you don't flip the rotation if H is on the left/right"

which one is correct?

This. You would just find which way the arc will be drawn from 1,2,3 and you flip the arc to get the stereoconfiguration.

 

[jmbusclas]

My trick that I give to all of my SI students for Fischers..

At first, pay no attention to where the low priority group is. Just number your priorities 1 through 4. Draw your arc so as to connect 1 to 2 (you may skip 4 but not 3).

Now, if the low priority group is on the Horizontal...your arc is Horribly wrong and you need to reverse the assignment. If your low priority group is on the Vertical...your arc is Very right and you leave it as is.