Okay, so let me first state what I know:
1. R is when the priority from 1 to 2 forms a clockwise direction
2. S is when the priority from 1 to 2 forms a counterclockwise direction
3. When assigning R or S, the priority 4 must be oriented away. If it's not, the 4th is flipped with whatever is oriented away, R or S is assigned, and then it is flipped. So R becomes S, and vice versa.
4. In a Fisher projection, the horizontal segment is out of the page and the vertical is into the page, hence the 4th priority should be in the bottom position (side question: is it the same thing if we make the switch such that the 4th priority goes to the top?)
Okay, now consider the following. Consider a molecule that has a single stereocenter. Suppose it is drawn sort of like a fisher but dashed lines are on the horizontals and wedges on the verticals (so now, the horizontals are going into the page). In this set up, is the switch to get the 4th priority on the right side or the left side? They are both pointed "back", so which one should have the 4th priority? Let me know if that doesn't make sense.
1. R is when the priority from 1 to 2 forms a clockwise direction
2. S is when the priority from 1 to 2 forms a counterclockwise direction
3. When assigning R or S, the priority 4 must be oriented away. If it's not, the 4th is flipped with whatever is oriented away, R or S is assigned, and then it is flipped. So R becomes S, and vice versa.
4. In a Fisher projection, the horizontal segment is out of the page and the vertical is into the page, hence the 4th priority should be in the bottom position (side question: is it the same thing if we make the switch such that the 4th priority goes to the top?)
Okay, now consider the following. Consider a molecule that has a single stereocenter. Suppose it is drawn sort of like a fisher but dashed lines are on the horizontals and wedges on the verticals (so now, the horizontals are going into the page). In this set up, is the switch to get the 4th priority on the right side or the left side? They are both pointed "back", so which one should have the 4th priority? Let me know if that doesn't make sense.
