Predict the major product of the following elimination reactio...

Question

Predict the major product of the following elimination reactions.

(a) Chemical structure showing an alcohol group (OH) and sulfuric acid (H2SO4) indicating a dehydration reaction.

Accepted Answer

Hi again everyone and welcome back in today's video, we are going to tackle the following problem which reads give the major products formed by dehydration of the given alcohols, threw sulfuric acid. We noticed that in particular in this problem we have two parts to solve. We are given two different alcohols and we wish supply the idea of dehydration to form the products. If we start with a we may retry our alcohol. We have 123456 carbon atoms, that's two hexagonal. So that would be our starting material. Because we're looking at the dehydration mechanism, we essentially may recall the major steps in the formation of products. The first step is that sulfuric acid is used in this reaction to protein. It the alcohol we need to use heat and sulfuric acid. We will essentially expand one of the hydrogen atoms And the remaining part of the molecule would be zero. 038 that sulfuric acid with one of the high Jin's expanded. There will be an attack the lone parent oxygen within the alcohol would get protein ated and we would have the loss of the leaving group. In this case, that would be the conservative base of sulfuric acid. We went saying a protein ated intermediate, which is a very good living group, isn't it? As possibly charged water molecule because oxygen now has a form of positive charge. We may indicate this stuff as the loss of the leaving group. So we would form a stable, actually quite stable secondary carbo Caroline riot is not the most stable one that we can get. So there will be a secondary carbo cara informed, we have to be extra careful and we have to thank perhaps we may form a more stable carbo Karen, but we don't have any possibility to form a tertiary one because we have hydrants here in here, a shift of this hygiene would still have a secondary carbo Karen. So this is our final carbo Karen that we want to use for this reaction. And our next step is to think about the beta hydrants because the next step is the actual elimination step. So the two beta hydrants that we're seeing are here and here because we're interested in the formation of the major product. We want to follow the same path through which says that we are moving the hydrogen that would form the most substitute at alk in And this is the one that we wish to remove. In addition, we generally consider bond rotation because there might be six version form. But since trans is more stable, we are going to produce a transaction is the major product. So we already have the right bond orientation in space. So the water molecule that we have formed previously will act as a weak base and we would have an attack. And that proton formation of the civil bond because these bonding electrons will be transferred into a pi bond and we would obtain our pound product, that would be the major product. There will be a double bond at this position and that's our final product. We are not interested in the two minor products. You may also notice that there will be a minor product if we remove this beta hydrogen or if we form a cyst is more of this trans compound because there's free bond rotation. So keep that in mind Now for B we have our alcohol. So let's draw that out. We we may recall the previous steps. The first step is the protein nation step because we have the dehydration mechanism, meaning the lumpy in oxygen will get protein ated similarly to the previous reaction. We're using sulfuric acid and heat so we may expand that acidic hydrogen. The lone pair gets protein ated. We have the loss the conjugate base. We are ready to draw the protein ated intermediate, which as you understand now, is a perfect leaving group. Just as we saw previously, if we have the loss of the leaving group, we will form a stable tertiary carbo Karen. So now we are ready to draw that, oh, sherry carbo cabron and we may now find our beta hydrogen for the elimination stuff. If you look at the position of the cardboard Karen, there are three beta hydrogen in particular surrounding it. There's one at this position, one The Jason and another one over here due to the line of symmetry passing through the carbon can iron. We understand that these two beta hydrants are equivalent to each other and this one is different from them. Now, these two are exactly the same and we have to choose whether we eliminate this hygiene or that one based on the dates of through we understand that our final product must be the most substituted al keen to ensure stability, meaning we are going to remove this one while the removal of the other one within the metal group would form a minor product. And because our goal is to get the major product, we are eliminating this hydrogen, forming a double bond and we will get our final product, which is the major product trying the final AL king. We add a double bond at this position so we may now label our answers for A. We formed the south team and for B. That's how I found product. The correct answer to this Multiple choice question is B However, if you have any questions, feel free to live down down below in the comments section

Predict the major product of the following elimination reactions.
(a)

Key Concepts

Elimination Reactions

Zaitsev's Rule

Regioselectivity

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