Відео

I love reactions involving azides, they are such a useful group! As for the next week reaction, the acid-promoted reaction of the ketone with methanol forms the hemiketal via nucleophilic attack of MeOH; the newly formed OH group then reacts with acid group to form a lactone, also favored under acidic conditions. And yes, I have already read in a comment that product is actually a ketone and it's just a mistake, so idk if it counts as cheating a bit 🙃 However, i am also pretty sure you can convert it into the drown reduced molecule using LiAlH4

a mechanism I really like

I’m getting to the lactone for next weeks product, and can’t see how one would get rid of the carbonyl under these conditions. Any hints

Love new mechanisms

I have one issue with the mechanism. At 1:28 you hace a n-c single bond and in the next step you have an n-c double bond without showing arrows forming the bond.

How did you do? I'd love to hear your proposals for next week's mechanism so drop them down below! Subscribe for more chemistry content, and hit the notification bell to stay updated! #ScienceCommunity #MechanismMonday #OrganicChemistry

Shouldn't it be a lactone in the product of nex week reaction?

Great content man!

Keep going 🎉😊

Cool synthesis! Does it work with other educts, too, e.g., with benzene, toluene, phenol, etc., instead of naphthalene?

Very interesting pathway. I was thinking more about something less selective but more brute force: 1.) Taking succinic acid and turning it into its acyl chloride 2.) Friedel-Crafts double dropwise acylation in dilute solution (high bp solvent) with a slight excess of naphthalene at >100C which is mainly expected to occur at the least crowded positions on the aromatic rings. Dilute and with slight excess because although the double carbonyl group is deactivating towards the aromatic system you still don’t want a double-substitution that makes a fused 4 ring system and you don’t want two naphthalene groups bridged by the succinic bit. 3.) Reduction of the carbonyl to alcohol with NaBH4 4.) Turning the diol into dibromide 5.) Reacting the dibromide with KOH in methanol to eliminate Br and H and form two alkene bonds, thus creating the new aromatic ring.

in the last step it feels more like an E1 mecanism since water is not a good base and also the formed carbocation is tertiary and so it is "stable"

Underrated creator

Can i ask the question? Do the reaction really occur and the yield of the reaction is huge enough ?

Thank you man, you save my Mondays

In which research article could I find this reaction or mechanistic study of this reaction? I can only find the thermal decomposition, hydroperoxy radical mediated decomposition, photodegredation and whole bunch of other things. Also, what about making a tert-butyl carbocation and making tert-butyl alcohol?

Do you suppose this mechanism would still be vaild for tert-butyl benzene.

How did you do? I'd love to hear your proposals for next week's mechanism so drop them down below! Subscribe for more chemistry content, and hit the notification bell to stay updated! #ScienceCommunity #MechanismMonday #OrganicChemistry

Very similar to BOC deprotection mechanism.

What’s a Fe(CN)6, did you mean K2[Fe(CN)6] or K3[Fe(CN)6]?

Could you do a birch reduction of the naphthalene, a Diels-Alder with 1,3-butadiene, and use an oxidizing agent like DDQ to rearomatize it?

I wonder if there is a way you can use the Bergman cyclisation? Perhaps you chlorinate the 2-position, then react with BuLi (Cl is an ortho directing group) and iodine to make 2-chloro-3-iodo naphthalene (and probably some 2-chloro-1-iodo naphthalene), then sonagshira with trimethylsilyl acetylene, cleavage of the silyl, then bergman cyclisation.

burch reaction isnt Na/NH3?

I made a problem based on this article. Ferricyanide doesn't form nitriles from sulfonates (or with at least an order of magnitude smaller yield). Thank you for the video and bringing up this topic. But, I would suggest you pay closer attention to drawing formulae, there are several mistakes

Amazing video for that anthracene synthesis, i usually forget about nitriles and their versatility. For the next transformation, I have thought in a kind of Robinson annulation, while trying to avoid the final elimination. In this reaction, 2-hexanone would be the Michael donor for acrolein, deprotonating the methyl group for the kinetic enolate, which attacks acrolein. After the reaction, the formed alcoxide (which tends to eliminate to form the enone) could be oxidized to a ketone, giving the product. Given this is a multistep exercise, let's assume we get the enone. We could oxidize that double bond to form the previously mentioned alcohol (I just dont remember how) and then convert it into a ketone. Another way to obtain the product would be with a Diels-Alder reaction with a Danishefsky-like diene, which would contain the propyl chain. Then, the aldehyde from acrolein would be degraded in a decarbonylaton reaction (e.g. the Tsuji-Wilkinson reaction). Finally, the 2 ketone groups be revealed, trying not to form the enone.

*fewer than five carbons.

Nice synthesis, I learned some new reactions !

Really nice procedure, and interesting last step! I ended up looking up methods for lateral expansion of aromatic rings, and I found in literature that acylation with succinic anhydride and reduction of the aryl ketone leads to a 4-aryl butyric acid intermediate, that can be ring closed with another acylation leading to an intermediate that is now the one ring expanded arene with the new ring still being aliphatic with the 1-carbon being a carbonyl group, which then can be dehyrated and thus aromatized with strong base (tBuOK) in DMAC and heating (150 C). Although maybe high heat in DMAC and strong base combo woud warrrant the use of a blast shield lol. Anyways it was an interesting synthetic excercise.

For the next problem I would use 1,3 cyclohexandione which has a pretty acidic a carbon as a nucleophile (actually it is very interesting why it is even more acidic than a linear 1,3 diketone - the conjugated system of the enolate is locked and the lack of rotation alines the π* orbital of the π bond with the lone pair when the a carbon in the middle gets deprotonated, the same reason explains the high acidity of Meldrum's acid), then a b addition occurs because the enolate is a soft nucleophile from the a carbon and the beta carbon of acrolein is a soft electrophile. Then the real fun begins because we should chemoselectively completely reduce the aldehyde and not the ketone FGs. I would use a thioacetal protection with ethanedithiol ideally at a low temperature, with low dithiol excess and for a short amount of time to ensure the thioacetal is formed selectively at the aldehyde since aldehydes are more reactive. Then an acetal protection at the 2 carbonyls and finally a catalytic hydrogenolysis with Raney Nickel of the thioacetal which reduces a thioacetal to an alkane. Deprotection of the 2 acetals using pTsOH with acetone will transacetalise the acetal protection of the 2 carbonyls of the substrate to acetone giving us the final product. Otherwise since the thioacetal protection is not a very common reaction and it is typically not used because of the extremely disturbing smell of the chemical, a Wolff-Kischner or a Clemmensen reduction would also completely reduce a carbonyl FG but I highly doubt that the process will be chemoselective.

what is stopping the sulfonate from adding to carbon number 1 of naphthalene in the first step?

I think that rxn requires very strong acid like Sulfuric acid which can break the aromaticity. Maybe hydrogen is added on the para position from hydroxy group. At that time, carbocation of meta position is pretty stabilized because its resonance form makes carbonyl compound which is stable than carbocation.(due to octet rule) And then HSO4- eliminates a hydrogen from t-butyl group to afford products.(driving force : recovery of aromaticity)

3 methods I did : 1. Using diels alder reaction with butadiene creates anthracene skeleton but adding further double bond might be tough which can be done by Pt(300°C) . However diene may attach anywhere in the whole naphtalene. 2. Malonic acid, using SOCl2 , gets acid chloride then Friedel craft acylation and reduction using NaBH4 followed by conc H2SO4(dehydrate) . This also gives some more products like phenanthrene etc. 3. Using 1-iodo, 2-(a good leaving grp like OTs) butane first performs anchimeric assistance, then naphthalene double bond attacks as nucleophile(maybe) followed by friedel craft alkylation, after which reduction again with Pt 300°C.

Great Video! Very excited for the new Format :)

Cool video! Though I think the diazonium reduction needs hypophosphrous acid to work. So H3PO2, not H3PO4. Phosphoric acid is not a reductant and would produce eithrer tribromophenol or the phsphoric acid ester of tribromophenol. Also, an easier way to do the first reaction in the lab is to use sodium cyanide to produce cyclohexyl cyanide, and reflux it in acid after a few water washes to remove sodium bromide and the remaining sodium cianide. The carboxylic acid should crystallize out after cooling back to r.t., so even though you do one extra step, you dont have to work up either steps and you dont have to flamedry glassware or deal with how finicky grignard reagents can be.

Thanks so much for tuning in! Join us for more exclusive multi-step synthesis videos here: ua-cam.com/channels/vZXVdaLlO1B6EDdR9s-m6w.htmljoin

Why do you suggest the E2 mechanism for the formation of the double bond instead of E1cb, which is typical of aldol condensation?

Hallo sir

Sir how to predict whether CO3 2- or the NH2 grp in the start will attack im confused. Also The k2co3 here is consumed but i hv usually seen reactions where it acts just as to get polar medium and does not take part in reactions

I did a mistake but really good question. The ring breaking step was nice

Maybe we can predict here, as a cyclic ketone in fairly acidic may form a carboxylic and since same molecule has hydroxyl, it will undergo esterification which occurs usually in acidic medium.

But tBuOk is bulky base so grabbing an acidic H from 1:45 here. But im not sure maybe it could

Funny lol enolate chemistry I thinky

Wow, that next week reaction looks crazy! Seems like a kind of retro-Friedel Crafts alkylation. My guess is, acid protonates the aromatic carbon holding the tertbutyl (which has more electrinuc density due to OH donating group), then the aromatic ring is restored by kicking out the tertbutyl gropu as a tertiary carbocation, which then forms isobutene in an E1 reaction, libersting a proton

So you want me to dissolve NaOH in EtOH😮‍💨

this reaction is routinely performed by undergraduate students, but the product they isolate is dibenzylideneacetone. maybe you'd be able to get this product with excess acetone present

That next one looks similar to the cumene process.

yay, i this was the first mechanism i was able to come up with pretty much on my own!

Great video as always, but the product is not cinnamaldehyde, it is not even an aldehyde

I'd like to request this interesting reaction: Dicyclohexylcarbodiimide (DCC) couples primary amines reaction.

My dream series as a chem student ❤🎉