Convert the following Fischer projections into tetrahedral representations, and assign R or S st

Convert the following Fischer projections into tetrahedral...

Key Concepts

Fischer Projections

Fischer projections are a way of representing three-dimensional molecules in two dimensions, particularly useful for carbohydrates and amino acids. In these projections, horizontal lines represent bonds coming out of the plane of the paper and vertical lines represent bonds going behind the plane. This visualization simplifies the analysis of stereochemistry and equivalence in molecules with multiple stereocenters.

Tetrahedral Representation

Tetrahedral representations depict the three-dimensional arrangement of atoms around a chiral center as a tetrahedron, which reflects the true spatial orientation of bonds. This conversion from a Fischer projection to a tetrahedral model is essential for accurately visualizing molecular geometry and understanding the stereochemical relationships among substituents.

Chirality (Chiral Center)

A chiral center is an atom, usually carbon, bonded to four distinct substituents, resulting in non-superimposable mirror images called enantiomers. The presence of a chiral center introduces asymmetry into molecules, which is crucial in determining their biological activity and physical properties.

Cahn–Ingold–Prelog Priority Rules and R/S Configuration

The Cahn–Ingold–Prelog (CIP) priority rules are a systematic method used to assign priorities to the substituents attached to a chiral center based on atomic number and connectivity. By applying these rules, chemists can determine the sequence of groups around the chiral center and assign an R (rectus) or S (sinister) configuration, which is key to understanding the molecule's stereochemistry.

Transcript

00:01 Okay, so for number two, we have these three fisher projections, and first we need to convert them to tetrahedral, and we're going to assign r or s configuration.

00:14 Okay, so let's go ahead and do that.

00:16 So starting with this first one right here.

00:19 Hopefully you remember that when you're looking at fisher projections, the one and the horizontal would be going out of the page, right? and the ones in the vertical line would be going into the page or away from you.

00:37 So when you're assigning r or s configuration, it makes it easier if you put the atom with the least priority in the back, right, which is usually hydrogen.

00:52 So i want to write this in a tetrahedral confirmation in such a way that hydrogen would be.

00:59 In the back okay so what i mean by that is if i have this thatrohedral molecule right here and this would be your your atom that's going towards you or out of the page and this would be the one going into the page right i want this i want this one to be hydrogen okay so that means this this other one would be your nh2, right? and then since hydrogen is going out of the, or into the page, sorry, which means the one on its left side would be the co2h.

01:56 So let's go ahead and put co2h here on the left, right? and then on the right side, you'll have that methyl group, okay? so now let's go ahead and assign priority to these, to this molecule.

02:17 So nitrogen, of course, is going to have priority.

02:22 So this would be one.

02:24 And then this carbon is attached to oxygens, two of them.

02:29 And then this is just attached to hydrogen.

02:31 So this would be your priority number two and this is three.

02:37 Okay so given that this gives us a counterclockwise kind of rotation which means this would be your s configuration right so we're going to do the same for the next two so this time i'm going to try to do it faster just for the sake of time right so again we're putting hydrogen behind right so we have this going out of the page and we have this one going into the page and that would be your hydrogen, which means this would be your oh.

03:25 Okay, so if you look at it, if you look at the hydrogen, on the right side would be your cho.

03:35 So right side of hydrogen would be cho, and on its left would be your methyl group...

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