Fischer Projections - Video Tutorials & Practice Problems

Fischer Projections Concept 1

Hey, everyone. So in this video, we're gonna talk about fisher projections. Now, they themselves are two D representations of chiral molecules where chiral centers is symbolized by the intersection of two lines. And here we're gonna have solid wedges. So these solid wedges here they are for our horizontal lines, the lines on the sides. And then here we're gonna have our dashed wedges or lines. So these are dashed. These are for our vertical lines here, we can transform this representation into a fisher projection. So what we do here is we would not show the carbon and we would show that carbon, which is chiral being connected to those same groups. Now, remember a chiral carbon or chiral center is when carbon is connected to four different groups. So we have XYZ and W here these are representative four different structures. All right. So then we're gonna write them in. So this would be Y up here, Z here, hold on, X here, Z here and W over here. So we've just created our Fisher projection and the carbon is still here. It's just invisible, it's still Cairo. So I'm putting an asterisk next to it to represent that it's still a chiral center, right? So, just remember here, we have the showing of our chiral carbon with wedged and dashed bonds. And we've just converted it into a Fisher projection where we have eliminated the stereo chemistry and made it two D. So the lines themselves no longer have wedge or dashed um representations.

Fischer Projections Concept 2

When drawing fisher projections, aldehyde and ketone groups are always represented on top. If we take a look here at this illustration, we start out with our bottom line form. Don't worry, you're not gonna have to convert from the bottom line form to the wedge dash form. So I'm just showing you that this here can be restructured to give us this form here. And it's in this form here. That's important for you to know how to go from it to your fisher projection. Now, remember your fisher projection is a two D representation. So we will not have stereo chemistry. That means we would eliminate these dashed bonds and these wedged bonds when drawing it. Now, here we have this, this and this as our chiral centers in terms of this um carbohydrate. And so this carbon here, we illustrate it as this carbon here. This carbon here would be this carbon here and this carbon here would be this carbon here. We already have our aldehyde here and we already have our C H2O H group here on the bottom. All we have to do now is just add what's connected to these three chiral carbons we have an H and an oh hoh and then hoh again. So we've gone from the wedge dash form to our fissure projection form which again is just a two D representation. Remove the stereo chemical bonds, no wedge bonds, no dash bonds to give us our fissure projection at the end.

Fischer Projections Example 1

Here it says, convert the wedge dash structure to a fission projection. Remember a official projection is a two D representation of our mono sac ride unit here. So that means we need to eliminate all our wedged and dashed bonds. So here we'd have still our C H2O H which we show uh here we not show the carbon but it's double bonded to the oxygen. And we have our two chiral carbons. Each one would still be connected to an oh and an H respectively. And then finally, we wrap it up with AC H2O H here on the bottom. So this would represent our Fisher projection where we've converted our wedge dash structure to it. Again, it's a two D representation need to eliminate your wedged and dashed bonds.