orgo general

[Anonymous No.7585526]

Hi friendos, time for /ogen/

>Recommend me a textbook
Wade, Clayden, Solomon, whatever. It doesn't actually matter too much, you just need to keep doing practice problems (I really like the problems in Bruice). Please don't shit up the thread asking for textbook recommendations.

>Guys I'm a future doctor taking organic next year. Tell me how to get a good grade!
Just make sure you memorize everything. Don't bother trying to understand the concepts, that's a waste of time. It's a lot easier if you just brute force your way through it and memorize all the mechanisms.

>How do I into synthesis research?
Go walk up to a professor and tell them you want to work in their lab. Most are glad to take on a new student, provided you aren't completely retarded -- you're basically free labour. Note that if your school has a lot of future doctor then you might have to compete with them on grades, some of them might also be bumming the prof so they could pad up their applications.

Also obligatory
>premeds need not apply

[Anonymous No.7585531]

Going to steal this shit from le reddit to make these threads more interesting; better than discussion about textbooks

>Propose a mechanism

[Anonymous No.7585540]

>tfw everything goes to shit and I have to start over and my coursework is starting to get really heavy and deadlines are chocking me

[Anonymous No.7585953]

>>7585531
Here's my attempt. I realize the triethylamine elimination is probably a kinetic red line though.

[Anonymous No.7586028]

>>7585953
What kind of fucking shit hand writing is that

[Anonymous No.7586076]

>>7586028
>handwriting aesthetic matters
ok anon

[Anonymous No.7586096]

>>7585953
jesus fucking christ

[Anonymous No.7586100]

>>7585531
extrusion of SO2 gives a diene which undergoes a Diels/Alder reaction with the maleimide

[Anonymous No.7586324]

>>7586100
>>7586096
Well fuck me sideways, a simple named reaction I'd just never heard of

[Anonymous No.7586335]

>>7586324
>takes orgo
>doesn't learn of Diels-Alder rxns
where'd you go to uni, m88?

[Anonymous No.7586350]

>>7586335
No I meant that chelotropic rearrangement. I never learned about sulfone reactions.
>textbook choice doesn't matter

Of course I know Diels-Alder.

[Anonymous No.7586416]

Richard Heck (as in the Heck reaction) passed away.
http://abcnews.go.com/Technology/wireStory/american-nobel-laureate-richard-heck-buried-manila-34434483

[Anonymous No.7586499]

>>7586416
Is chemistry past the era of named reactions? What's the most recently developed reaction that's named after someone?

[Anonymous No.7586502]

OK anons, what about this

[Anonymous No.7586504]

>>7586502
Also R = menthyl, and also there's an aqueous Na2SO3 workup after step one

[Anonymous No.7586526]

>>7586504
Should that be TMSO?

[Anonymous No.7586612]

anons what are the Woodward-Fieser rules good for (other than a teaching tool or whatever) if we could get the lambda max accurately using a spec

[Anonymous No.7586946]

>>7586028
I like it. it has character.

[Anonymous No.7587205]

>>7586502
Step 1: TMS group replaced w/ bromine. Probably by a stereoretentive Se2.
Step 2: Sn1 w/ assistance from silver counterion. The ester can trap the carbocation and then can undergo methanolysis to yield the free hydroxyl and that the resultant orthoester decomposes down to the methyl ester. Regioselectivity a function of the exo- ester being able to reach the carbocation (the endo is on the wrong face of the bicycle).

[Anonymous No.7587340]

>>7587205
>stereoretentive Se2.
explain

[Anonymous No.7587739]

>>7587340
Sn2 by definition proceeds with inversion of configuration because of the necessary orbital overlap. Because in an electrophilic substitution your existent bond contains the electrons to be used in the next bond, the requirement for orbital overlap can occur with retention or inversion. Both can occur. It really just depends on your mechanism.

If you can find an old copy of Mechanism and Theory by Richardson and Lowry [dirt cheap to get the actual text too], they have a nice explanation of it.

[Anonymous No.7587770]

>>7587205
Why shouldn't it proceed through bromonium ion formation and norbornyl rearrangement?

Can you provide a mechanism for this stereoretentive TMS displacement you propose?

[Anonymous No.7587836]

>>7587770
I was worried about the stereochemistry of that at first but it turns out it works out OK now that I've drawn it out because of the trans arrangement of the esters. I looked it up, and you can actually isolate a brominated/silylated intermediate in this reaction so an Se2/i is definitely not correct.

[Anonymous No.7587881]

R is trimethylsilylethoxycarbonyl.

Propose a reaction--I did this tonight--it's not too bad.

[Anonymous No.7587935]

>>7586096
>>7586100
>>7586335
HAHAHA GUESS WHAT YOU GUYS
https://www.reddit.com/r/chemistry/comments/3ogg6q/mechanism_monday_its_been_a_while/
REKT

[Anonymous No.7588030]

>>7587881
ozonolysis of the alkene gives an aldehyde,
acetylide addition to the aldehyde gives a propargylic alcohol,
Mitsunobu to make the lactone

[Anonymous No.7588065]

>>7588030
I meant to say propose a mechanism. an aldehyde isn't made--the DMS will do a slightly different reduction. Also, what about the stereochemistry? Why is it the way it is in the product.

Mostly right though--just gotta consider the carboxylic acid. Also, it may be helpful to note an excess of grignard is used

[Anonymous No.7588161]

Would anyone be able to tell me whether the mechanism for this reaction proceeds through the starred resonance contributor? I feel like I've tried everything I can do with it and still can't reach the product, so I'm worried that I've just been barking up the wrong tree.

[Anonymous No.7588181]

>>7588161

[Anonymous No.7588191]

>>7588181
Suddenly I feel pretty stupid. That was way simpler than I was making it. So the carbon radical can then get the CCl3 that it needs but how would the double bond be removed at that point? Or should that just be dealt with before the intramolecular ring formation?

[Anonymous No.7588198]

>>7588181
dude those arrows are 2sick

also you write like a girl lel

[Anonymous No.7588206]

>>7588191
running into a problem justifying regioselectivity of the addition of .CCl3 to the pi-bond

>>7588198
I'm a fat neckbeard, take it up with cambridge soft.

[Anonymous No.7588210]

>>7588206
Thanks anon that helps a ton. For the most part I just needed to figure out a mechanism the regioselectivity is sort of an afterthought.

[Anonymous No.7588216]

>>7588210
Another thought
Instead of reacting the .CCl3 directly with the alkene, do another allylic C-H abstraction to give an allylic radical. Then combine .CCl3 with that radical.
It 'fixes' one regioselectivity problem, but introduces another. (Why wouldn't the abstraction occur at the tertiary allylic ponsition?)

[Anonymous No.7588225]

>>7588216
That also sounds plausible. I would assume the secondary allylic position is favored due to there being two possible hydrogens to abstract?

[Anonymous No.7588312]

Here's a trivial one. Propose a mechanism.

[Anonymous No.7588326]

>>7588312

[Anonymous No.7588340]

>>7588326
how are you posting these mechanisms so neatly

like is there some software youre using

[Anonymous No.7588343]

>>7588340
Perkin-Elmer will send a geisha to your basement dwelling to give you personal lessons in the fine art of chemical calligraphy!

fuck you for inducing me to respond seriously
https://www.cambridgesoft.com/software/overview.aspx?cid=3984&gclid=CKjjg9DawcgCFU9gfgodiRQNCA

[Anonymous No.7588716]

What do you guys think are the big problems in synthetic organic chemistry? I think the field is starting to really grip the power of radical chemistry, but I don't necessarily see how the field advances after we fully explore that domain. Do we find better methods of asymmetric induction? Unique methods of substrate activation? Meticulous catalyst design for designer bond activations?

[Anonymous No.7590212]

>>7588326
>acid anhydride enolates

[Anonymous No.7590789]

>>7590212
>not offering an alternative proposal
;)

[Anonymous No.7590793]

>>7588312

DUDE METH LMAO

[Anonymous No.7590797]

>>7588065

DMS has to take the ozonolysis product to the aledehyde oxidation level, do you mean that the product cyclises under the conditions to give a hemiacetal? (Hemiacylal?)

And then the ethynylmagnesium bromide attacks from the convex face but then the carbon it attacks gets inverted by the intramolecular Mitsunobu.

[Anonymous No.7590802]

>>7590797
Not the guy who posed the problem but
>DMS has to take the ozonolysis product to the aledehyde oxidation level
yes, I agree - that's what my notes say b/c the DMS serves to reduce the molozonide/carbonyl oxide to ensure that the products are two carbonyl compounds

>do you mean that the product cyclises under the conditions to give a hemiacetal? (Hemiacylal?)
I don't remember the name of the functional group either - I though it was lactol (like hemi-acetal but from an aldhyde and a carboxylic acid rather than an aldehyde and an alcohol).

[Anonymous No.7590816]

>>7590802

Nah, a lactol is a cyclic hemiacetal from an aldehyde and an alcohol. Lactam is a cyclic ester.

Acylals are pic related but I don't know whether the name changes without specifically an acetyl group or in a cyclic situation, I'm just making it up as I go along.

[Anonymous No.7590920]

>>7590816
>Lactam is a cyclic ester.

Fuck, I meant lactone.

[Anonymous No.7591249]

>>7588326
Nah, you're book-keeping is all fucked up. You're missing an oxygen from the former anhydride.

1. Base catalyzes formation of the mixed anhydride
2. Enolize @ the benzylic side and trap an acyl group
3. Free acetate converts your acylated anhydride back into a beta keto acid
4. Decarboxylation

Idea is that you can't enolize @ the benzylic position if you have a carboxylic acid (much more acidic), so once you mask that as an anhydride you can acylate. Once you revert back to the carboxylate you can then decarboxylate and viola.

[Anonymous No.7591665]

>>7588065

You'd better come back and tell us what the right answer is I tell you what

[Anonymous No.7591834]

I'm looking around for paid internships this spring, but haven't found any openings yet. Where should I be looking if I want reasearch experience? I'm a senior undergrad with a good amount of research experience

[Anonymous No.7591919]

Hey bro pass me your chemistry textbook real quick

[Anonymous No.7591937]

>>7590802
>>7591665
Sorry, hombres. Here it is with a bit of an explanation

[Anonymous No.7591963]

>>7591937

I forgot the Felkin Anh rule, hooray for stereochemistry.

[Anonymous No.7592017]

>>7591937
is that hemiacetal a good electrophile? Why wouldn't the grignard just attack the aldehyde?

[Anonymous No.7592067]

>>7592017

The lactol form is in equilibrium with the aldehyde.

[Anonymous No.7592076]

>>7592017
The structure on the lower right is the resulting compound from step 1. Once the grignard is added, it will take the proton on the alcohol first, then an intramolecular collapse occurs, giving a carboxylate and an aldehyde--the second grignard will attack this aldehyde.

>>7591963
Boatloads of fun. I thought it'd be the Cram Chelate model, but both carbonyl oxygens would make a 7-member ring, and the N is basically part of an amide and not nucleophilic.

I don't know why the carbonyl on the other side doesn't do anything in the reaction though. They guys that did this reaction only got about 90-ish% yield, so I guess there were some side products.

[Anonymous No.7592191]

>>7591919
REEEEEEEEEEEEEE

[Anonymous No.7592439]

>>7592076
so you're using two equivalents of grignard to react with an aldehyde? what's your source for this?

[Anonymous No.7592944]

>>7592439
I think they use an excess.

Enantioselective Total Synthesis of (−)-Acetylaranotin, a Dihydrooxepine Epidithiodiketopiperazine

It's a JACS paper

[Anonymous No.7593433]

>>7591249
>back into a beta keto acid
beta what?

[Anonymous No.7593560]

>>7593433

Your structure there is wrong.

[Anonymous No.7593562]

Does anyone actually enjoy orgo lab

[Anonymous No.7593566]

>>7593562
Undergrad orgo labs I mean

[Anonymous No.7593751]

Asked in another thread, but how do I maintain 99.9% acetone while being opened and exposed to humidity whenever I use it? What's the best drying agent that doesn't chemically react with it?

[Anonymous No.7593785]

>>7593433
You don't trap at the benzylic position with acetate, just an acyl group. Basically just remove your non-carbonyl oxygen from your structure and hydrolize the anhydride and that's what I mean.

[Anonymous No.7594020]

>>7593751
3A molecular sieves

or just distill that shit under nitrogen fam and keep it in a flask with a septum as a stopper with some 3A molecular sieves in there for good measure

[Anonymous No.7594044]

>>7594020

Molecular sieves aren't good for acetone long-term as they're mildly basic and will cause aldol reactions.

>>7593751

Why do you need it so pure?

[Anonymous No.7594052]

>>7588326

[Anonymous No.7594055]

LIke dude I just nitrated some cotton balls and woosh, they go up without a trace, and I get to thinking... Is there any other shit around the house I can replace the OH's with other than NO3? What would I end up with? Is any of it cool?

[Anonymous No.7594075]

>>7594044
>Molecular sieves aren't good for acetone long-term as they're mildly basic and will cause aldol reactions.

shit didn't know that, thanks anon

I use it for methanol all the time but never used it for acetone before, just assumed it'll work

[Anonymous No.7594320]

>>7593751
The real question is, why is it opened and exposed to humidity?

[Anonymous No.7594604]

>>7594052
>stoichiometric amounts of thionyl chloride and methyllithium
Spot the guy who's obviously never run an illicit lab

[Anonymous No.7594623]

>>7594604
what would you do?

I work in an organic synthesis lad for big pharma and I'd like to see you get fewer than 2 steps

[Anonymous No.7594769]

>>7594623
Why not use a Gilman?

[Anonymous No.7594784]

>>7594769
ahhhh you bastard I knew there was some variation that I'd forgotten that was more nucleophilic than basic

[Anonymous No.7594805]

>>7594052
what's the point? isn't phenylacetic acid just as illegal and controlled as phenacetone

[Anonymous No.7594923]

>>7594805
pretty easy to make tbh

[Anonymous No.7595008]

>>7594052

>mono-addition of a Grignard to an acid chloride without overreaction to the tertiary alcohol

Good luck anon

[Anonymous No.7595305]

>>7594805
No, it's a DEA-listed compound so purchase as an individual sends up red flags, but its not scheduled and a feedstock in several industries. Easy enough to divert.

>>7594923
>>7594623
Clandestine synthesis is different from bench research. Alkyllithiums and other expensive stoichiometric reagents tend to be avoided. Recreational drugs are as a rule much cheaper than well-designed, therapeutic drugs and they're not propped up by the artificial liquidity of the health insurance racket. Legitimate fronts also have fairly limited use, and can't be used to wantonly buy the best reagents for the job when they're out of place in their industries. The scale is generally large enough to make routine lab procedures like drying ether and religiously excluding moisture for a grignard difficult, but small enough to make full-on industrial process engineering a waste of money. Simple reactions are prized above ingenious ones.
The "industry standard" for unsubstituted amphetamine is nitroaldol condensation of benzaldehyde and nitroethane, then reduction with hydrogen over transition metal catalyst. Benzaldehyde is a non-petroleum derived feedstock, so you can be green while you ruin lives and families.

[Anonymous No.7595410]

>>7595305
>nitroaldol condensation of benzaldehyde and nitroethane, then reduction with hydrogen over transition metal catalyst.
I'd call that more genius than things like wittig/grignard tbh. Industry processes fascinate me, they take a whole other form of logic

[Anonymous No.7595422]

>>7595305
The first time I did drugs and thought they were more amazing than they really are, I figured out a decently simple synthesis of some fun amphetamine from very cheap, very benign looking compounds. Chemicals for developing photographic film and the like are a good source, and the cutting-edge chemistry of the beginning of the last century is pretty easy to do in your garage. Re-arrangements are wonderful reactions.

[Anonymous No.7595526]

>>7595410
One crafty technique is human ingestion of unsubstituted phenethylamine (very cheap and rapidly degraded by monoamine oxidases) and isolation of phenylacetic acid from the urine. Recombinant bacteria expressing MAO then lend themselves to a more efficient (and dare i say cleaner?) scale-up. Similarly, stereospecific production of phenylpropan-1-ol-2-one from benzaldehyde by s. cerevisiae, z. priorianus and others under anaerobic conditions is well-documented, reductive amination of which gives enantioenriched product which is carried to the terminal steps in the usual manner.

Enzymes: they're not just for Pfizer anymore.

[Anonymous No.7595615]

>>7593566
I was just following the cookbook but yeah sure, I guess.

[Anonymous No.7595820]

>>7595422

Are you going to tell us what the synthesis was or just be all smug about knowing it?

[Anonymous No.7595824]

>>7590816
>Acylals
hemi-acylal
yes, that's the term I couldn't come up with

[Anonymous No.7595852]

>>7591249
>You're missing an oxygen from the former anhydride
No: 6 O-atoms (3 from the mixed anhydride and 3 from the enolate of the symmetrical anhydride) w/in the bracket and then on the RHS: ONa is 1, OAc is 2 more, (CO)-OAc is 3 more - that's 6.

>1. Base catalyzes formation of the mixed anhydride
yes

>>7591249
>2
>3
>4
You are proposing pic related?
I like the assertion that the position which is both benzylic and alpha-to a carbonyl is more acidic than acetic anhydride itself. I think you are correct.

How do you address this: >>7590212 ?
My inclination is to admit the difficulty of preparing acid anhydride enolates stoichiometically but to continue to suggest that they are viable as transient low conc. intermediates (subject to other pathways - elimination to give a ketene?- no one in thread has said anything about experimentally determined yield of the methyl ketone).

18O labeling to the rescue?

[Anonymous No.7595857]

>>7595852
even better, 13C labeling

[Anonymous No.7595872]

>>7595526
Holy fuck that's dank
I'm floored by how clever that is

[Anonymous No.7596068]

>>7595852

Look up the Perkin reaction in "Strategic applications of named reactions in organic synthesis", no need for speculation here.

[Anonymous No.7596097]

>>7595852
Addressing >acid anhydride enolates

People have done asymmetric enolate chemistry of acid chlorides with cinchona alkaloids, with the idea of first forming the ketene and then having the cinchona alkaloid add in to form a zwitterionic enolate. Mayr gives a nucleophile parameter of 16.9 (MeCN) for acetate and 15.66 (MeCN) for 2-(naphthylmethyl)quinuclidine, which would imply that acetate is close to the same nucleophilicity and thereby capable of similar reactivity.

For nucleophilicity parameters, see: http://www.cup.lmu.de/oc/mayr/reaktionsdatenbank/

Acetate is under carboxylates, the quinuclidine in question is under pyridines and quinolines.

[Anonymous No.7596131]

>>7585526
>Don't bother trying to understand the concepts, that's a waste of time. It's a lot easier if you just brute force your way through it and memorize all the mechanisms.

[Anonymous No.7596296]

>>7596131
That's the joke.

[Anonymous No.7596302]

>undergraduate orgo
> 99% memorization of which catalyst goes with which reaction and only partially intuitive reaction mechanisms
>all exam questions about synthesis
>hate it

>PhD orgo
>taught by synthesis specialist
>hardly talks about reactions, spends most of the time on molecular orbitals and stability
>like it a lot more

[Anonymous No.7596913]

>>7586502
Not necessarily related to this question, but what conditions would you need to generate this intermediate in red?

[Anonymous No.7596971]

>>7585531
B is [Co(CO)4]-, 18e- complex, formed by reduction of dicobalt octacarbonyl, which is 17e-. C is formed by the nucleophilic attack of tetracarbonylcobaltate on trifluoroacetic anhydride, followed by decarbonylation of the resulting metal aldehyde complex to give the trifluromethyl complex.

[Anonymous No.7596973]

>>7596302
your undergrad orgo was a shit course lmfao. unfortunately 95% of all undergrad organic courses are like this, no emphasis on the principles behind why certain mechanisms go certain ways

[Anonymous No.7596980]

>>7585526
why the fuck is your TsCl in a metal can?

[Anonymous No.7596991]

>>7588343
kek'd fuckin hard

[Anonymous No.7596992]

>>7596980
That's how a lot of these things ship: there's a white poly bottle inside per usual.

>>7596913
No idea, but making that bromide is going to be incredible difficult in the first place because you need to outcompete formation of the lactone per the first mechanism this was involved with. The cis-exo product may be very difficult to make too...

[Anonymous No.7596994]

>>7596992
wtf

I always order new batches from aldrich and its never been packed in anything except for a glass jar. It isn't even particularly stenchy...

[Anonymous No.7597215]

>>7596913

Your second step to generate the thing in the red box just wouldn't happen, that's crazy.

What's the broader context?

[Anonymous No.7597288]

>>7596973
Any good books for this? Using McMurry and Wade, but this shit still feels nonintuitive. Not the guy you're responding to btw, just taking Orgo 2 and I love it but hate it.

[Anonymous No.7597322]

What do medicinal chemists do exactly? Would I be a synthetic organic chemist that also gets to test his compounds on cell cultures and mice and shit? Would it be easier to find a job as a medicinal chemist or synthetic organic chemist?

[Anonymous No.7597343]

>>7597322
>What do medicinal chemists do exactly?

They make target compounds and get activity data. Then the game becomes trying to deduce structure-activity relationships among others. It's a *ton* of synthetic chemistry.

[Anonymous No.7597687]

>>7597322
we make fucking small molc drugs based on SARs. It is harder than manufacturing labor but we get paid less....

[Anonymous No.7597725]

>>7597322
I have a background in chemical engineering, but I work in a molecule discovery lab. We do mRNA display (https://en.wikipedia.org/wiki/MRNA_display)) to develop small peptides that selectively bind to a target of interest.

These can be used to do all sorts of things (think of any case where you would need a highly specific ligand to a protein or something), but we focus on assay development and drug design, working in tandem with pharma companies.

[Anonymous No.7598202]

I used to get chemdraw via my university but I left and can't re-download.

Are there any free chemistry drawing programs that even come close? I'd rather not pirate it from totally_legit_software.ru and end up with a dozen trojans.

[Anonymous No.7598223]

>>7597687
>>7597725

How hard was it to find a job? How much do you get paid? Are you satisfied with it or are you getting cucked? What are your qualifications? Would you get paid more if you had a PhD?

[Anonymous No.7599151]

What is your favourite way to make an alkyne /sci/?

I expect no sensible answers at all but it is a way to bump the thread.

I made one via the Bodendorf reaction which was quite exciting really and makes a good story to tell girls at the bar.

[Anonymous No.7599240]

>>7599151
Sonogashira coupling

[Anonymous No.7599395]

>>7598223
>How hard was it to find a job?
There are no low-level chemistry jobs right now.

Chemist 1 and 2 do not exist.

It fucking sucks. C&EN wrote some really great damage control articles after the boston ACS conference this year. "200 jobs, 900 jobs seekers"


Fuck this world

[Anonymous No.7599398]

>>7599151
who the fuck uses alkynes

just use do a suzuki with the boronate that you need and skip that shit

[Anonymous No.7599399]

>>7599240

I'm not sure it counts as making an alkyne if you start with the alkyne bond already formed.

[Anonymous No.7599564]

>>7599151
corey fuchs is pretty beautiful, I'd love to try it sometime

[Anonymous No.7599578]

I'm not very knowledgeable on organic chemistry but for some reason I love these threads.
Maybe it's partly because they seem like one of the last refuges for people who have actually seen the inside of a university on this board.

[Anonymous No.7599644]

>>7595305
What alkylating reagent do they use to make the final product?

[Anonymous No.7599695]

>tfw when you aced orgo and already forgot everything

[Anonymous No.7599939]

>>7599395
Do you think it's getting better or worse? What's the most thriving field of chemistry right now?

[Anonymous No.7599972]

Is Klein's Organic Chemistry a decent book?

[Anonymous No.7599990]

>>7599399
Depends on situation. If it makes you feel better, Ohira Bestman isn't bad

[Anonymous No.7599995]

>>7599695
>tfw you got a C and remember most the concepts

[Anonymous No.7600063]

>>7599990
That ugly reagent though

[Anonymous No.7600325]

>>7599564

It's not beautiful when you're generating shitloads of cottage-cheese-like triphenylphosphine oxide.

On paper it's a nice reaction, but in modern chemistry there's no excuse for using about 1200 Da of reagents and incorporating 12 Da of that into your product. I've done one and you aren't missing anything by having not.

[Anonymous No.7601056]

>>7600063

>calling the Ohira-Bestman reagent ugly

I'll fight you IRL

[Anonymous No.7601820]

>>7600325
agreed

>>7600063
Have you ever done an OB?

[Anonymous No.7602057]

>>7600325
>in modern chemistry there's no excuse for using about 1200 Da of reagents and incorporating 12 Da of that into your product.

Unless it's carbohydrate chemistry boyo
>Just protect/deprotect my shit up

[Anonymous No.7602271]

>>7601820
yeah, my bad I just forgot the c-f uses 4eq or phosphine

[Anonymous No.7602431]

>>7597215
>Your second step to generate the thing in the red box just wouldn't happen, that's crazy.
I know it's crazy, I'm wondering if it's possible. The bromine is anti- to the bond being broken, meaning it could eliminate E2. TMS can stabilize the cation via beta-silicon effect, and reverse diels-alder reactions have been known to happen in ontrolled settings
>What's the broader context?
Understanding the power and limitations to eliminations, beta-silicon, and retro diels-alder effects

[Anonymous No.7602766]

>>7602431

There's no driving force for the bromide to just fall off and leave a carbocation in its wake via such a complicated process. And in fact, what you've drawn isn't actually a retro Diels-Alder given that the bromid leaves, it's more of a fragmentation reaction.

[Anonymous No.7602858]

>>7602057

I don't have my copy of Classics to hand but I remember there was some step at the end of a Nicolau synthesis with about 30 equivalents of TESOTf, lel.

[Anonymous No.7603522]

I saw Phil Baran at a grocery store in Los Angeles yesterday. I told him how cool it was to meet him in person and congratulated him on his synthesis of Palau'amine, but I didn’t want to be a douche and bother him and ask him for photos or anything.

He said, “Oh, like you’re doing now?”

I was taken aback, and all I could say was “Huh?” but he kept cutting me off and going “huh? huh? huh?” and closing his hand shut in front of my face. I walked away and continued with my shopping, and I heard him chuckle as I walked off. When I came to pay for my stuff up front I saw him trying to walk out the doors with like fifteen Milky Ways in his hands without paying.

The girl at the counter was very nice about it and professional, and was like “Sir, you need to pay for those first.” At first he kept pretending to be tired and not hear her, but eventually turned back around and brought them to the counter.

When she took one of the bars and started scanning it multiple times, he stopped her and told her to scan them each individually “to prevent any electrical infetterence,” and then turned around and winked at me. I don’t even think that’s a word. After she scanned each bar and put them in a bag and started to say the price, he kept interrupting her by yawning really loudly.

[Anonymous No.7603537]

At home way to remove the water from liquor store 95% ethanol?

[Anonymous No.7603857]

>>7603537
Can't be done, water and ethanol form an azeotrope and can't be distilled conventionally. If you want to make pure ethanol use benzene.

[Anonymous No.7603962]

>>7585526
how do i into ochem?
I'm a little faggot who's about to graduate HS and I want to study Chemistry. Is there any point right now? Any jobs? is BioChem better?

[Anonymous No.7604106]

>>7603857
lots and lots of anhydrous calcium sulfate

[Anonymous No.7604109]

>>7603962
just do engineering, take it from a chemist who doesn't want to go into academia and is desperately searching for jobs now

also underage b&?

[Anonymous No.7604159]

>>7604109
10 days underage b&
give me a 10 day ban if you want. just make sure it expires 30.10.2015 at 0 AM gmt+2

[Anonymous No.7604328]

>>7604159
Happy birthday faggot.
Ochem is something you'd only do because you enjoy it, job market is not good at all rn

[Anonymous No.7604528]

>>7603522
fucking kek

/sci/ needs more organic copypastas

Someone please write an angry rant about EJ Corey and his snuff fetish

[Anonymous No.7604532]

>>7603537
Add KOH and let it sit

Also bake a SHITLOAD of sieves and just fill that shit up; immediately pull off with a dean stark

[Anonymous No.7604594]

>>7603857
Maybe extract it out with another solvent that you could distill away,?

[Anonymous No.7604599]

>>7604594
>extract it out

extract a low MW alcohol and tell us where to send your nobel pryze

[Anonymous No.7605243]

Puzzled... why does the benzene ring have a greater inductive effect on the hydrogen, making the compound MORE acidic than the one with the N(Me)2 group. Or does this have to do more with nitrogen's inductive effects being mitigated by its neighbors?

[Anonymous No.7605394]

>>7605243
This kind of H-acidity question is best solved by considering the deprotonated entity. Now, my chemistry is getting rusty so don't quote me on this, but...

• If you remove the proton in C, you can only delocalize the electron density of the negative charge on the carbonyl group, which competes with the delocalization of the electron-rich nitrogen's lone pair. Which means your negative charge can spread over 3 atoms tops.

• When you strip the proton from D, the negative charge is conjugated with the whole pi-system, into which it can "pour" some of its electron density. The charge then spread over all 9 atoms.

[Anonymous No.7605467]

>>7605394
is there a way to better visualize this? i'm not >>7605243 , but still interested to see the effect of deprotonation on the electron density and how much it shifts.

[Anonymous No.7605699]

>>7605394
>>7605467
Hand waving intensifies

[Anonymous No.7605823]

>>7605394
You can't donate by resonance into the arene. Or, at least, you cannot draw a resonance structure with one, negative formal charge delocalized in the arene. This explanation cannot be correct.

The better explanation: the nitrogen lone pair and the arene pi system can donate into the ketone pi antibonding orbital. The nitrogen lone pair is a much better donor than the arene system. The consequence of any mixing is that you raise the energy of unpopulated orbitals (i.e., antibonding orbitals) on the carbonyl, with better mixing (i.e., better donation) increasing the energy of the orbital.

When you deprotonate at the alpha carbon, that charge is stabilized by delocalization into the carbonyl pi antibonding orbital. Because the nitrogen is a good lone pair donor, the charge is less effectively delocalized into the carbonyl and thus the pKa is relatively high. Alternatively, because the arene is such a poor electron donor the charge is effectively delocalized into the carbonyl and thus the pKa is relatively lower.

[Anonymous No.7605851]

>>7603857

thanks for the note. I'm just isolating and concentrating capsacin and wanted to try and get my etoh purer but whatever, 95% works for. I want to keep it edible so I'm just gonna go with what I have.

[Anonymous No.7607640]

>post your favorite reaction

[Anonymous No.7607651]

>>7607640
The easiest solutions are usually the best.

[Anonymous No.7607713]

>>7607640
staudinger

[Anonymous No.7607725]

>>7585526
I'm not a chemist, where can I get a basic run down of how to name chemicals and stuff? I need to not sound like an idiot in front of chemists.

[Anonymous No.7607885]

>>7607640

Fritsch-Buttenberg-Wiechell rearrangement.

Don't have a picture because fuck you.

[Anonymous No.7608075]

>>7605699
why exactly?
do you mean you can't explain it?

[Anonymous No.7608096]

>>7607725
im sure you can find quizzes and what not
it's really just practice and memorization from using the compounds
memorizing functional groups would help, but most of the time that alone won't exactly give you the name of the compound. You have to realize that there are also common names that are kind of arbitrary, while there are many acceptable names based on the structure of the molecule

[Anonymous No.7608106]

>>7596973
its not so hard lel pretty much everything is based off of acid-base chemistry and sterics
if you can't see that you're not too bright

[Anonymous No.7608113]

>>7607640
i guess I would have to say the huisgen 1,3 dipolar cycloaddition, since I'm writing a paper on it right now and its pretty cool I guess

[Anonymous No.7608968]

>>7607651

>favourite reaction is hydration of an alkene

I bet you're a scream at parties

You'll never be able to pick up chicks by telling them about Markovnikov's rule, they are excited by edgy modern shit like the Chan-Lam coupling or the Davis-Beirut reaction.

[Anonymous No.7609047]

>>7608968
>davis-beiruit reaction
ayyyyyyyyy lmao

>not picking a based reaction like the chromium hetero-claisen, crabbe homologation, or limonene transfer hydrogenation

[Anonymous No.7609059]

>>7585526
What's the secret? My textbook just goes blindly through mechanisms without explaining why they happen. My tests are entirely pairing reagents with products.

[Anonymous No.7610120]

>>7609047

I'll be honest, I didn't know about the Crabbe homologation but I looked it up and that shit is INTENSE.

[Anonymous No.7610361]

>>7610120
It works for everything, which is nice, but the waste produced is kind of shitty to deal with. All in all, probably one of the easier ways to make an allene though.

[Anonymous No.7610678]

>>7608075
It means you're giving non rigorous answers.

[Anonymous No.7610732]

>>7610678
i'm not >>7605394. Was just asking for a visualization of what he had explained.