00:04
Here we are given four reactions and asked to draw the products of the reaction and what the most likely mechanism is that these would react by.
00:16
I think these questions are out of order.
00:19
I think it would make a lot more sense for us to determine what mechanism it is first before we try to determine the products, since the mechanism is going to help us determine the products.
00:31
So first let's remind ourselves what the difference between sn1 or sn2.
00:36
Is what indicates that something would be reacting by one mechanism or the other.
00:42
So if we take a look at sn1 versus sn2, remember that sn2 is fast, it's concerted, and so it has to have a reaction center that is unhindered and able to react quickly.
00:57
So that's going to be our methylhalides, primary, and secondary centers.
01:07
Can it be tertiary? no, it cannot.
01:12
We cannot do tertiary sn2 reactions.
01:16
Sn1, however, is stabilized by having a larger reaction center.
01:21
So tertiary is better.
01:23
Secondary is all right.
01:25
And those are the two that we're going to, those are the ones we're going to see here and those are the ones we're going to focus on.
01:31
Sn2, we also know that we're going to have a strong nuclear file.
01:37
For sn1, of course, it'll be weak.
01:43
And that's enough for us to identify the reactions we have here.
01:48
So for a, we'll start out, let's figure out if this is going to be an sn1 or an sn2.
01:55
The first thing i'm looking at is my reactant, my nuclear file.
02:01
I recognize this as methanol.
02:03
That's a solvent.
02:04
That is going to be weak.
02:07
There are no charges or anything like that.
02:11
It's going to be weak.
02:13
Looking at a reaction center over here.
02:16
I see we have one, two, three, that is a tertiary center.
02:22
There is no doubt about it.
02:24
This is going to react by an sn1 mechanism because we're looking at tertiary and a weak nucleophile.
02:32
Now, to determine the products, we know that sn1 reactions always result in a racemic mixture because of the carbocadion leaving.
02:43
But because all of our molecules here start out racemic, we're always going to, for the molecules that we have here, we're always going to see a racemic mixture, meaning we have half of our product with the nucleophile on the front side coming out of the screen and our remaining groups going into the screen.
03:13
So after deprotonation and everything, we can write out the mechanism for this, but the question we just have to give the product.
03:21
I know that it would replace our chlorine.
03:28
The methanol would replace the chlorine.
03:30
The hydrogen would be deprotonated.
03:32
And we would be left with this, with this structure.
03:40
Now, let's take a look at b.
03:43
I'm going to do the same thing.
03:44
Let's look at the nuclear file.
03:45
I see a charge.
03:47
So right away, i'm going to say this is a strong nucleophile.
03:51
This looks also like oh, and we know that sulfur and oxygen are cousins...