Nef Reaction (Introduction to Umpolung Chemistry)

The Nef reaction is a good way to convert nitronates into carbonyl compounds. This is a technique that can be incorporated into a strategy called "Umpolung", which refers to a reversal of polarity, such that upon converting from the nitronate to the carbonyl after some addition has occurred, structures can be afforded that would be difficult to come by when performing carbonyl chemistry. Let's look at the mechanism and some applications!

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[glennpearson]

Umpolung?! Saying the word reminds of the German bands I used to listen to in Bavaria during Oktoberfest.

This one went way over my head, Professor Dave, but I enjoyed it all the same. More great science content from one of the best in the business.

[BradSchmor]

Another example of umpolung with nitroalkyl groups is the Henry reaction. If done under dehydrating conditions, the resultant nitroalkene is an excellent Michael acceptor and allows you to build up the chain quickly. Optimizing the Henry condensation can be seriously challenging sometimes, though.

[michaelathens]

Hey I remember this one. Haven't thought about the nef reaction in ages, cool refresher!

[markshort]

I thought you were going to say umpolumpa for a second 🤣

[Bunnys]

As a trained electro-mechanic and now a software and games programmer, I have to say when it comes to chemistry I'm certainly trapped in the "valley of despair" :) Whenever you think you went up the slope of enlightenment just a little bit, you just slip down again to the bottom when a new video of Dave comes out :D.

Nevertheless, even though I understood only 5%, I find it humbling to see what people have come up with and what they have figured out about our world. My former physics teacher always made fun of chemistry as it's just a subset of particle phyiscs. While this is technically true, it kind of missed the point. While phyiscs can explain how particles interact with each other, it's not suitable to reason about material properties and macro scale effects. It's like looking at individual bit in computer memory, seeing 1s and 0s and trying to reason about the story of the RPG game that is currently running. That would be pretty stupid. Drawing programming analogies, I would say when physics could be compared to machine code / assembler, chemistry would be a specialized high level language. All that happens in chemistry has its basis in plain physics, but it's much easier to work in the higher level language.

Isn't it amazing what the internet can provide us? Every piece of information and knowledge is just some clicks away. Yes, there is a huge potential for misinformation spreading (antivax, flatearth, anit-science, anit-government, alternative medicine and even black people voting trump and denying racism), though I hope in the long run people understand the value of the scientific method... if they only would understand it.

Even in my own family there always was a bit esoteric involved (like homeopathy). However since the corona pandemie they have gone full force anti establishment, anti vax and world conspiracy. At the moment I realised there's no hope to "convince" them or change their mind. They trapped themselfs in several echo chambers which is really sad. I just hope time will solve some of the issues. Though with the Ukraine war things are not getting better...

Anyways, keep up the great work. Getting some insight into the work of other fields is just great. Perfect place to accumulate some dangerous sciolism :)

[kd]

Hi professor, would this nitronate-carbonyl followed by nef reaction approach be preferred over the dithiane umpolung? i would think that, even though both would achieve the same 1, 4-diketone, the dithiane approach would require lesser steps and give greater yields? i am aware that dithiane would require the handling of mecuric salts. may i know what are your thoughts?

[Mathew]

omg how many named reactions are there in organic chemistry

[banu]

How to turn off incandescent torch light in present of which chemical reaction

[jeromebirth]

Have any of these chemical reactions been tested on the ISS in zero gravity to see if it is easier, or more difficult to net results?

[abhay]

Hey, professor hope you are doing good as always, I already owe you a lot, however, a small request, I implore you to make a detailed playlist of videos, of ECOLOGY as there aren't many good sources to cover this portion.

[Messmer_da_Impaler]

Hey, i just wanna know if you think kurgzgesagt are a good source of information or not

[HardToBeAPoopGod]

i'm German and didn't even read 'Umpolung' as a German word LOL i read it as some like, native Canadian last name

[BenStJohn-rmmp]

Small note: I'm pretty sure (given the German) it should be pronounced "oom-POLE-ung"

[jbirdmax]

Isn’t umpolung what you get when you vape too much?
😂