[Winga]

e.g.
If I draw a fischer projection of a compound with two chiral centers like this (vertically):
_CH3
I+OH
I+Cl
_COOH

("_" is meaningless, just for creating a space)

There is no problem to find the priorities of the substituents in the first (upper) chiral carbon.

However, the upper vertical branch of the second chiral carbon is out of screen (paper), and how about the carboxylic carbon? Out of screen?

We still follow the rules of fischer projection? So that, the structure bends into the screen just like forming a ring?
 

[dexangeles]

here i drew you something
it's a little wacky drawing but hey it helps lol

just remember:

1. the pink arrow shows you your view of the molecule from the fischer projection point of view.  this means the middle C-C bond in actually flat on the screen/paper

2. for the saw horse to be drawn in fischer, it has to be oriented the same way, the one C is rotated, so when you see it from above, both verticals are going away, and the horizontals are towards you (like arms wanting a hug )

[Winga]

A new question:

Is (2R,4S)-pentane-2,4-diol a meso compound?

[movies]

Well, what is the definition of a meso compound?  What symmetry element is required?

[jena]

Hi,

meso compound has a achiral carbon so it has symmetry

[movies]

meso compound has a achiral carbon so it has symmetry

It's more specific than just an achiral carbon.  Meso compounds are achiral, but not all achiral compounds are meso.  Do you know what symmetry element is required for a compound to be meso?

[Mitch]

Meso compounds are achiral, but not all achiral compounds are meso.

Stereochemistry, my old nemisis.

[dexangeles]

Hi,

meso compound has a achiral carbon so it has symmetry

meso example: achiral molecule with 2 chirality centers