Retrosynthesis 4 - Organic Chemistry

[@julianr.82]

I think the Horner-Wadsworth-Emmons-Reaction would be favourable instead of the classic Wittig, cause you can purify your products easily

[@singularityJoe]

Nice discussion

[@CasualChemistry]

Thanks for the feedback 🙂 Glad you enjoyed the video

[@singularityJoe]

@@CasualChemistry with targets like this, the racemic variant is nice for sophomore organic, but it would be cool if you discussed some enantioselective variants for more advanced tactics. It's not so obvious to me how one could install that stereocenter

[@singularityJoe]

I guess you could have the phenyl butanoic chiral imide, asymmetric methylation, transform to ethyl ketone via weinreb amide with cuprate, then benzylic oxidation delivers the aldol substrate

[@CasualChemistry]

I’m up for making some videos on asymmetric retrosynthesis but I figured I’d go for some racemic stuff first while I work out what I’m doing with KZbin. In fact I’ve made my videos on some common asymmetric catalysts already to allow me to do some more advanced other videos and work out who my audience are. My background is in natural product total synthesis and will definitely be exploring those areas going forwards.

[@singularityJoe]

@@CasualChemistry sounds great! I'm working in a total synth lab as well. Will check out other vids.

[@chrisboyall8602]

What level of study is umpolung chemistry taught? I don’t think I’ve ever heard of this sort of chemistry before

[@CasualChemistry]

I’d probably place it somewhere in the middle of an undergraduate course in Chemistry. I think the most important pre-requisites are knowledge of a few specific enolate equivalents and being comfortable with the hard/soft reactivity ideas in organic chemistry. In my opinion introducing these concepts is also setting the stage for introducing heterocyclic chemistry (especially 5 membered rings). So if I were designing a course I’d place it there as a topic. This video was sort of a deliberate one that I could have on my channel to complement any nitrogen heterocycle videos I plan/planned to make.

[@chrisboyall8602]

@@CasualChemistry hmm, we never got taught this sort of methodology in my undergrad. However, it is probably one of the most fascinating techniques I’ve heard of so far, such an intelligent strategy.

[@YoAddicts]

@@chrisboyall8602 Same. I've only ever heard of "umpolung" in my master's degree, and we were studying organometallic chemistry.

[@C134B]

Idk, i would have gone the other way, with pyrrolidine, 5-pentanone and NaNH2 or N,N dimethylhydrazine, pentanone and BuLi to attack the phenylmethyl ketone, previously brominated in acidic conticions. The nitropropane thing i didn't think of, thanks. pd: sorry for the broken english, i'm writing this in a hurry

[@CasualChemistry]

👍 There’s definitely lots of alternatives not covered in this video for a molecule like this. I went for some that I thought would hopefully be interesting/useful.

[@smmcknnn]

Nazarov cyclization would be ideal

[@CasualChemistry]

Indeed it would🙂 yes, there’s definitely lots of routes. I biased this video towards a “traditional” Umpolung direction partly so I could use it as a reference for other videos.