Draw the major product of each of the following reactions: |...

Name: Problem 27, Chapter 10: Organic Chemistry
Uploaded: 2020-07-25T03:25:44-08:00
Duration: 7 min 11 s
Channel: Tom Rutherford
Description: Draw the major product of each of the following reactions:

Key Concepts

Reaction Mechanisms

This concept involves understanding the step-by-step process by which reactants transform into products. It includes analyzing electron movement, intermediates, transition states, and the overall pathway a reaction takes, all of which are crucial when predicting products in organic reactions.

Major vs Minor Products

This concept deals with the outcome of reactions that can produce multiple products. It entails determining which product forms in higher yield (the major product) based on factors such as the relative stability of intermediates, kinetic versus thermodynamic control, and the reaction conditions.

Regioselectivity

Regioselectivity refers to the preference for chemical bond formation at one direction or position over others in a molecule during a reaction. This concept is especially important in reactions that produce different positional isomers, where rules like Markovnikov's dictate the predominant product.

Stereoselectivity

Stereoselectivity is concerned with the formation of one stereoisomer over others when multiple stereochemical outcomes are possible. Understanding this concept is key in predicting the spatial arrangement of atoms in the major product, particularly in reactions involving chiral centers or geometrical isomerism.

Reagent Effects and Reaction Conditions

The specific reagents and conditions (such as solvent, temperature, catalysts, and concentration) play a crucial role in directing the course of a reaction. These factors can influence the reaction mechanism and the selectivity, thereby impacting which product becomes the major one.

Transcript

00:01 Okay, this problem is asking us to predict the products of each of these reactions.

00:04 So first things first, i'm going to go to the first one.

00:06 I notice that i have an epoxide and i have the hcl and methanol.

00:10 Okay, so what i'm going to do is i recognize i'm in acidic conditions, so i'm going to go straight away and protonate my oxygen, because that's the most basic atom of this molecule.

00:18 Okay, so it should be left with this.

00:21 My protein is the epoxide with a positive charge, and then the remainder of my compound.

00:26 Okay, so now i have to consider my chloride, and then i have to consider my methanol.

00:33 Okay, so what's going to happen is my methanol is going to be the one that is behaving as a nucleophile, okay? because it's better nucleophile than my chloride.

00:40 Okay, so my methanol is going to come in and attack one of these two carbons.

00:45 Okay, we don't know which one yet.

00:46 Let's discuss this.

00:48 So, if it were to attack this carbon, then that would mean that i would have to move the electrons onto that oxygen.

00:54 Okay, so that's an option.

00:55 The other option is it attacks this carbon, and i move the electrons that one.

00:59 Way.

01:00 So which is the correct one? the correct one is the one that is kind of a mixture between the sn1 type of reaction and the s &2 type of reaction.

01:07 Because right now, this all is going to happen on the same step.

01:10 Okay, it's going to be basically occurring simultaneously where i have my nucleophile attack and my electrophile, sorry, my leading group leave, but it's not going to behave in the same exact way as an s &2.

01:20 So it's a mixture of sn1 and s in two.

01:22 So what i'm going to do is i have to recognize that the addition of this hydrogen makes it so that this bond right here is super weak because i have the auction with a positive charge.

01:34 Oxygen is so electronegative, it doesn't want to have that positive charge.

01:37 It wants to have as much electron density around it as possible.

01:41 And with the addition of that positive charge, it makes it less so.

01:43 So it's going to want to kind of withdraw electrons towards it so that i can have that electron density around it.

01:50 So it has a choice.

01:51 It can either take electrons primarily from this carbon, that bond, or primarily from this carbon bond.

01:56 And it's going to take it primarily from this carbon bond.

01:58 So i'm going to be basically pushing electron density towards that auction.

02:02 And if i do that, then i'll create a partial positives or partial positives on the carbons.

02:09 So for example, if i have my bond right there, i'm going to have a slight dipole moment on this carbon.

02:16 Okay.

02:16 So we can kind of think of that as a carbocadion because if i were to just straight up move the electrons onto that auction, then we would be left with a tertiary carbonate iron right there.

02:26 So it's the same thing, except we're dealing with, you know, dipoles.

02:29 Okay, so it's a slight partial positive there and then that's a slight partial negative right there because it's pushing electron density or pulling electron density towards it.

02:39 Okay, so with that in mind, i'm going to use my methanol to attack that carbon, the super electropositive carbon.

02:46 Okay, and in the process of doing that, i'm going to have to move the electrons up to the auction to create this compound.

02:52 So there's my alcohol.

02:54 Here's its bond.

02:55 So this bond right here is this bond right there.

02:59 Okay.

02:59 Next.

02:59 Next up, i'm going to force this one over, and then next up is the connection to my two methyl groups and the connection to my methanol.

03:09 Just like this.

03:10 Okay, and then, of course, i have my protonated methanol, but we can just alleviate that with another methanol.

03:17 Or even my chloride.

03:18 So let's just use my chloride so we can have some differences.

03:22 Okay, so my chloride is going to go ahead and tack that.

03:24 We're leaving that methanol of its positive charge, so we get this as my product.

03:31 Okay, so just like that...

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