/sci/ - Science & Math » Thread #13075020

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Help me solve this

Anonymous Tue 04 May 15:36:34 2021 No.13075020 View Reply Original Report

Quoted By: >>13075211 >>13075296 >>13075471 >>13075478 >>13076350 >>13080604 >>13082709

please help chembros

Anonymous

Anonymous Tue 04 May 2021 15:52:37 No.13075182 Report

Quoted By:

I'll give you a hint: what mechanism do you need to follow to produce you intermediates? You should be asking yourself, does the reaction follow an elimination type process or a nucleophilic substitution type process?

Your E1, E2, SN1, SN2 reactions all give different intermediates and products. Try to analyze your synthesis reagent ( HBr ) and determine what kind of process it ought to favor.

>tldr; I'm not doing your homework for you, but I'll nudge you in the right direction.
>t.chemist grad

Anonymous

Anonymous Tue 04 May 2021 15:56:06 No.13075211 Report

Quoted By: >>13075223

>>13075020
wtf is this question even asking
what is "order from start to finish"

Anonymous

Anonymous Tue 04 May 2021 15:59:03 No.13075223 Report

Quoted By:

>>13075211
It's asking the reader to put, in sequence, the intermediates that form from the reaction. Certain ions/compounds will form over the course of the reaction before they themselves react. The paper wants you to show that sequence of formation of intermediates.

Anonymous

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Anonymous Tue 04 May 2021 16:10:27 No.13075283 Report

Quoted By:

I'll use the synthesis of acetanilide from aniline as an simpler example.

Aniline is our reactant, the acetic anhydride is our reagent, and acetanilide is our product.

Now, when you bring your reactant and reagent together for synthesis, it's not "ZOOP!" and you have acetanilide. There is a step-by-step process of reaction where unstable, reactive intermediate compounds form before they stabilize into our final products of the synthesis.

The purpose of this homework is to get you to realize what compounds are your reactants, what compounds are your reagents, and the pertinent conditions that might drive your reaction to favor a certain type of process.
In particular, you need to be able to look at a syn th hesis and immediately recognize your nucleophiles and electrophiles and the likely couplings they will produce.

Anonymous

Anonymous Tue 04 May 2021 16:11:51 No.13075296 Report

Quoted By: >>13075391 >>13079670

>>13075020
you should know that the first step is protonation
then consider what mechanisms a secondary and tertiary group will undergo
that should help you figure out what kind of intermediates you'll get and in what order

Anonymous

Anonymous Tue 04 May 2021 16:27:39 No.13075391 Report

Quoted By:

>>13075296
Maybe I'm a bit callous but giving anon the first step of the reaction will hardly help if they haven't bothered to do the cursory reading on mechanisms.
He'll just want us to spoon-feed him on the next intermediate because he has no idea where to proceed to from this new information.

Anonymous

Anonymous Tue 04 May 2021 16:44:45 No.13075471 Report

Quoted By: >>13075551

>>13075020
This is trivial

Anonymous

Anonymous Tue 04 May 2021 16:47:24 No.13075478 Report

Quoted By: >>13075509

>>13075020
I think Bromine is more electronegative than Oxygen, so Br wants to get rid of its H, and the O has lone electrons to get the H.

Next, that carbon becomes positive and the Br will donate electrons there.

It has been awhile since I looked at any chemistry and I sucked at it then

Anonymous

Anonymous Tue 04 May 2021 16:50:33 No.13075490 Report

Quoted By: >>13075495 >>13075501

Looks like J->D/H

Anonymous

Anonymous Tue 04 May 2021 16:52:08 No.13075495 Report

Quoted By:

>>13075490
With A as an intermediate

Anonymous

Anonymous Tue 04 May 2021 16:53:21 No.13075501 Report

Quoted By:

>>13075490
It's not because the reaction states "excess HBr".
There's another set of intermediates as a result to remove the excess.

Anonymous

Anonymous Tue 04 May 2021 16:55:05 No.13075509 Report

Quoted By: >>13075564 >>13079670

>>13075478
My second step looks dumb...The O that formed the O-H bond becomes positive.
Next the Br bonds to the C and the O-C bond will break with those electrons going to the O

Anonymous

Anonymous Tue 04 May 2021 17:06:07 No.13075551 Report

Quoted By:

>>13075471
Duh, this is mechanisms homework for O-Chem 1 students.

Anonymous

Anonymous Tue 04 May 2021 17:09:38 No.13075564 Report

Quoted By:

>>13075509
You're moving along in the right direction. What you need to do now is observe which of the two carbons will form the most stable carbocation.

Anonymous

Anonymous Tue 04 May 2021 19:10:32 No.13076183 Report

Quoted By:

Hey OP, we haven't heard back from you in a long minute. Do you got this, or do you still want help?

Anonymous

Anonymous Tue 04 May 2021 19:35:44 No.13076350 Report

Quoted By: >>13076849

>>13075020
J is the first obviously

Anonymous

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Anonymous Tue 04 May 2021 21:16:14 No.13076849 Report

Quoted By: >>13078896

>>13076350

Anonymous

Anonymous Wed 05 May 2021 07:59:07 No.13078896 Report

Quoted By: >>13079670

>>13076849
in every possible ether cleavage mediated by an acid with the ether not having other reactive groups the first step is always protonation of the ether oxygen

Anonymous

Anonymous Wed 05 May 2021 13:38:42 No.13079670 Report

Quoted By:

>>13078896
Anon, we already established this:

>>13075296
>>13075509

Anonymous

Anonymous Wed 05 May 2021 16:59:28 No.13080604 Report

Quoted By: >>13080733 >>13082045

>>13075020
Is there a logic behind this or is this entirely something you memorize? What's the rule for these synthesis reactions?
I took 4 chemistry classes and passed them all in my undergrad but I'm still shit at chemistry.

Anonymous

Anonymous Wed 05 May 2021 17:21:23 No.13080733 Report

Quoted By:

>>13080604
To be honest, it's both. You're going to have to memorize substitution/elimination mechanisms for electrophile/nucleophile reactions at the very bare minimum. From here, you can general "logic out" a reaction from a set of reactants, reagents, and conditions.

Anonymous

Anonymous Wed 05 May 2021 20:33:44 No.13082045 Report

Quoted By:

>>13080604
most undergrad courses explain chem at a surface level so it's hard for most people to wrap their heads around
so yes there is logic behind it, however, at a lower level it's mainly memorization

Anonymous

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Anonymous Wed 05 May 2021 21:55:53 No.13082709 Report

Quoted By: >>13083366

>>13075020
i got a C+ last year, but it was remote work so who knows

Anonymous

Anonymous Wed 05 May 2021 22:33:26 No.13083366 Report

Quoted By:

>>13082709
Alright, not bad.

You got most of the first half, but remember, there's an excess of HBr which is still available to react with any of your products from your first step.

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