In this video we're going to solve the chair conformations bonus quiz question B: turning
a chair conformation into a newman projection. You can find the entire quiz along with the
chair conformation tutorial series on my website at leah4sci.com/Chairs. Make sure you also
review Newman Projections tutorial series linked below or leah4sci.com/NewmanProjections.
The tricky part in going from a chair conformation to a newman projection, is that you're taking
a molecule presented in one strange way of looking at it and converting it into another
way of strange way of looking at. Right? Chairs and newman are just different ways of looking
at molecules. The trick to simplify this is to recognize what you're looking at and find
a way to make the initial chair directly look like a newman projection. In the Newman Projection
series, I teach you to take the carbons that you're looking at and imagine wrapping your
fingers around it to create that newman projection ring. So we are going to sit ourselves right
here facing the chair conformation. So this is you facing the molecule, this is the back
of your head, your hair, you're looking in that direction. And you're taking your hands
and wrapping it around the sides of the chair. You're holding the model in a way that your
fingers create that newman projection ring. These represent your fingers, this will be
your hands, let's take a look.
This chair conformation does not have all the substituents we saw in the example but
the concept will be the same. You want to imagine that you're isolating the ring and
only focusing on these two carbon atoms right here. If this is going to be our newman projection,
imagine grabbing the ring, wrapping your hand around, this will give you that circle that
you'll see in newman projections. We're holding it right here, front carbon is visible, rear
carbon is not because we're blocking it and that's okay. So long as the rear substituents
are showing, which we'll try to see past my fingers, we have the methyl group going out
there, we have a hydrogen down there, we have that red hydrogen and then the rest of the
ring. We'll do the same thing to the other side, we're looking at these two carbons,
we're looking from this one down to this one so we take our fingers, wrap it around and
when you hold your chair like this and I want you to start imagining right there is where
your newman projections starts to form.
Instead of hands, let's draw that as the newman projection ring so we'll put one circle right
here, and another one right here. With a standard newman projection you see three bonds coming
out of the front of the newman and three bonds behind it. They can be written as a y or an
upside down y. And when going from a chair to a newman, instead of picking which one,
let the chair show you, by first adding in all the invisible hydrogen atoms on the right
and left carbons of the chair. On the right lower carbon, we have a methyl group going
down so that means we have a hydrogen in the equatorial up position. Here we have a hydrogen
in the axial up, hydrogen equatorial down, and hydrogen axial down. Why do we need to
see this? Ask yourself, based on seeing the three atoms coming out of this carbon, do
I have a y? or an upside down y? We'll have to use our imaginations to tweak it a little
bit but here, we have a y and here we have the upside down y. On the other side, upside
down y, and regular y. This is really all you need to see. Everything else will fall
into place when you redraw it. Start with your hands we'll try the circles and place
your y or upside down y. On the right we have a y in the front, upside down y in the back.
On the left we have a y in the front and upside down y in the back. Then it simply a matter
of copy and paste.
On forward carbon we have a methyl group in the down position, we have a hydrogen up right,
and in the up left position we have a carbon that connects the right newman projection
to the left to complete the ring. Instead of a CH2 which you normally expect, in this
case we have a fluorine and a hydrogen so that's a CHF and we can simply draw that here
as CHF or you can draw it here as CH and show the F going down. You might have to tweak
it a little and reform your y so it connects to that CH group. Let's move on back. For
the rear carbon on the right, we have a hydrogen in the up position, we have an isopropoxy,
isopropyl on an Oxygen giving me an ether going down and towards the right. And towards
the left we have a CH2 that connects the ring. So that right here would be a CH2. Moving
over to the carbons on the left, for the forward carbon, up and towards the right, we have
an OH group. Down is a hydrogen and we already have the CHF over here in the up position.
For the rear carbon in the up position, we have a carboxylic acid, going down and towards
the left we have a hydrogen atom which completes the newman projection.
At this point, make sure that every carbon has the correct number of attached groups.
Start with the newman and make sure your y or upside down y does have the three things
attached where the middle is the carbon that connects the right and left side of the ring.
We have one, two, three. One, two, three, one, two, three, and one, two, three. To summarize,
the trick here is to imagine grabbing the model kit here and here. Figuring out if your
carbons have the y or upside down y and then superimposing all of your substituents.
Make sure you try the rest of the quiz on my website leah4sci.com/chairs.