JEE Chemistry Club

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Gaurang Tandon

00:59

@Abcd hmm right right I was mistaken

@Abcd yep mistake

@Abcd I checked and have understood

4 hours later…

Avnish Kabaj

05:13

The heck is diels alder

Anything can happen in chem

4 hours later…

Gaurang Tandon

09:24

@AvnishKabaj not in jee course

1 hour later…

Jasmine

10:36

@RaviPrakash No, not possible. Resonance or hyperconjugation is possible only when the functional group departs from substrate. It is possible in vinyl alcohol, halide, amine, etc where lone pair is on group.

@GaurangTandon what dies alder not in jee portion?

@Abcd and sn1 and sn2 prime is in jee portion

Jasmine

10:53

Has anyone here got proper jee course (complete)?

Gaurang Tandon

@Jasmine you can get it on jeeadv.ac.in website

Jasmine

Yeah @GaurangTandon but is every single topic encluded?

Gaurang Tandon

@Jasmine well, they don't always ask questions on every single topic. like this year in mains they left out a few

@Abcd @AvnishKabaj @samjoe and all, how to differentiate between product A and C. A is formed by nucleophilic attack of phenolic oxygen atom on t-butyl cation, while C is formed by EAS of t-butyl cation on phenolic ring. Which one is major and why?

Jasmine

@GaurangTandon but dies alder is in portion isn't it

Gaurang Tandon

@Jasmine no, it isn't.

Jasmine

11:00

No it's there for sure.

Gaurang Tandon

okay let me check

Jasmine

@GaurangTandon we have had a good long class on it its there for sure

Gaurang Tandon

@Jasmine sorry but your long class probably got wasted. here's the syllabus - jeeadv.ac.in//Syllabus.html

Jasmine

Can't believe it @GaurangTandon

According to me c should be correct I may be wrong what's the answer @GaurangTandon

Gaurang Tandon

@Jasmine yes, C is right!

why not A though?

Jasmine

11:21

At a go I just thought of EAS as oh is strongly activating so go for it for major

And don't you think it would be more difficult for a bulkier group to attack

Gaurang Tandon

@Jasmine hmm, could be that's the reason

the electrophile is very branched, sterically hindered

Jasmine

Yeah

Gaurang Tandon

thanks @Jasmine

Jasmine

Yeah @GaurangTandon

Koolman

12:20

@GaurangTandon I think It depends on temperature .

I am not sure

Gaurang Tandon

now I am also wondering that - since the t-butyl group is sterically hindered - then wouldn't the EAS face trouble as well?

@Koolman oh! could be though

Koolman

It can be asked on main site

Gaurang Tandon

yep @Koolman, but I was just looking to get a confirmation here once

to make sure i'm not overlooking something easy

Jasmine

12:37

Oh yeah I didn't notice Tempe rature now what?

Gaurang Tandon

let the other three guys drop in and give their opinion, if there's nothing easier i'll post on main

2 hours later…

Avnish Kabaj

14:32

@GaurangTandon (C) EAS

And I don't remember properly but if (A) gets formed then at high temperature won't claisen condensation take place

Or is that only for Alkenes

Gaurang Tandon

@AvnishKabaj no, i don't have a clue

Avnish Kabaj

My bad claisen rearrangement not condensation

Gaurang Tandon

@AvnishKabaj i don't think that would happen organic-chemistry.org/namedreactions/claisen-rearrangement.shtm

Avnish Kabaj

Dunno why wouldn't (A) form

Gaurang Tandon

i'm posting on main

Abcd is super late

Jasmine

14:41

@GaurangTandon my Teacher said for sure dies alder in portion and everything is not mentioned on the official site

Gaurang Tandon

@Jasmine well, it's fine if you've learned it, there's no harm in learning more stuff...

Jasmine

@GaurangTandon but its in portion. End of it. I wont argue anymore on this

Gaurang Tandon

14:58

I think I now know why @AvnishKabaj @Jasmine: the lone pair of electrons on the oxygen atom in phenol is delocalised, so it ain't as nucleophilic as we expect it to be

2 hours later…

Jasmine

16:33

Oh! Yes correct logic. @GaurangTandon

But still its nucleophilic not to that extent but in minor the product a should also be formed

And temperature has it got anything to do with the reaction

Abcd

@GaurangTandon What happened? I return from FIITJEE at 9 pm.

@AvnishKabaj that's only for allyl vinyl ether or allyl phenyl ether

@GaurangTandon The point is concentrated $ \ce{H2SO4}$. Phenol isn't a good nucleophile and in acidic medium nucleophilicity just decreases more.

Whenever than H+ leaves phenol after it has attached to Carbon atom of the carbocation, it comes back.

While the EAS is more feasilble here, there are no such difficulties in the pathway.

@GaurangTandon Right, and acidic medium decreases it more.

Abcd

17:00

High temperature ensures the formation of the para isomer as the major.

Gaurang Tandon

@Abcd woah, sorry, didn't know that. That's honestly really late

@Abcd got it dude, thanks!

Abcd

@Jasmine Okay thanks. It's very easy though. I have studied it.

@GaurangTandon Ring opening reactions of epoxides in acidic or basic medium, both result in Walden inversion of the electrophilic chiral centre carbon.

Abcd

17:36

Q: SN1 reactivity order for chloromethyl ether and trityl chloride

Compare the reactivity order towards SN1 reaction for: Cyclopropylethyl chloride $\ce{CH3OCH2Cl}$ $\ce{Ph3CCl}$ Owing to the exceptional stability of cyclopropyl ethyl carbocation (see), obviously it should be on the top. We did this question in class and my teacher told me ...

@GaurangTandon Bounty suggestion. This can even be asked in JEE 2018...then everyone willl be confused whether they should follow the order given in march or not.

Sourabh Yelluru

18:06

Hey, I am getting the no. of chiral centres in reserpine to be 9 . Whats wrong with me?

Could someone point out the mistake I might be doing.

Jasmine

18:25

@SourabhYelluru you might be counting N as chiral centre but that wont be correct

Jasmine

18:39

@Abcd D is correct.

I think you are too confused with it so am I. But majority would agree to D being correct.

Abcd

@Jasmine yes I know... We cleared it that day from Clayden

@Jasmine Why are you confused? What are you confused about?

Tell me, I'll clear your confusion.

Jasmine

In some books the order is wrong

Abcd

@Jasmine which books

1 min ago, by Abcd

@Jasmine Why are you confused? What are you confused about?

@Jasmine that day (I think it was yestrday)... we also concluded using ron's answer that allylic free radical is more stable than benzylic free radical

Free radical not carbocation.

Benzylic carbocation is more stable than allylic one

Jasmine

Yes

Abcd

so whats the chemistry confusion right now?

What do you want to know?

Jasmine

18:44

This is wrong stability order

Abcd

Duh that idiotic OP Tandon's book.

Please dont use it.

Jasmine

Yeah.

Abcd

@Jasmine Yes

Jasmine

Then its ok.

My teacher also said benzylic more than allylic

Abcd

@Jasmine Please dont use that book. I have heard it has many errors.

Jasmine

18:46

Ok.

Abcd

A: Why is allyl chloride more reactive towards substitution than alkyl chloride?

But how allyl halide is more reactive than alkyl halide? Reactivity towards $\ce{S_N1}$ The key to reactivity towards $\ce{S_N1}$ is the stability of the formed carbocation. Allyl system stabilises the carbocation through overlap with the vacant p orbital (@gsurfer999 has shown the resonanc...

See the tables from Clayden.

Abcd

18:59

Anyway, good night.

Abcd

19:29

@WeijunZhou know what buddy, I saw a dream last night where I saw this order for E2 mechanism: 3∘>2∘>1∘. Now I have a firm belief that this order is correct. Just like Kekule's structure of benzene which he predicted based on the dream he saw where a snake was whirling around a campfire lol. — Carrick Jan 30 at 15:20

Jasmine

Is clayden a very good book? Better than solomon?

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