Evans Auxiliaries and a Friend for Aldol Reactions

[@void-ux5cl]

Love how your videos are always easy to follow yet detailed, keep it up mate

[@CasualChemistry]

Thanks 🙂 More in the pipeline including an extension on this one.

[@aurelius388]

I agree. The way Mr. CasualChemistry builds it up is impressive, and it is clear that he really understands and sees organic chemistry. The collection of Paterson aldol methodology is powerful and especially suited for polyketide products. The syn/anti-switch with Bn/Bz, respectively, is something that I had forgotten about. I only remembered the Bz/anti (probably due to the formyl hydrogen bond). Thank you for your efforts and I look forward to the next video!@@CasualChemistry

[@CasualChemistry]

Sounds like you might have an idea where the next video will pick up from. Got some other stuff I want to touch on. The next video will hopefully wrap up a loose trilogy of connected topics

[@Alcaloide_Reactif]

Thank you from France ! I really appreciate the clearity of the message

[@CasualChemistry]

Thanks 🙂 Took a bit of time to work out what I wanted to say on this topic and this feedback is very much appreciated

[@liammccreary2941]

This is by far the best explanation of this material I’ve ever seen! Thank you for making this video, this’ll help so much with my syntheses!

[@CasualChemistry]

🙂 Thanks. It’s been bugging me for a while that this topic can get confusing if lecturers try to rush explanations. I’ve been meaning to make this particular video for ages

[@alexbeatson1887]

I just want to say you give the clearest explanations I have seen on this topic. Clearly you truly understand what your are teaching!! Sick of seeing others use stupid logic to predict products of asymmetric Aldo’s reactions. You bring everting back to fundamental concepts and I love it!

[@CasualChemistry]

😎 Thanks. What you say was exactly my motivation for starting the channel in the first place. Making ‘tricks’ and ‘ways of remembering’ for organic chemistry is missing the whole point of the subject in my opinion.

[@aurelius388]

Nice to see that you draw what Stuart Warren called atom-specific curly arrows - as seen for the aldol reaction at 0:44.

[@CasualChemistry]

I might have unconsciously picked that up from him in lectures back in the day 🙂 Very useful in complex molecules for sure so very much a habit

[@chemistrydemystified9923]

Was waiting for your video. Thanks

[@CasualChemistry]

You’re welcome 🙂 I’ve re-recorded this a few times to get the message I wanted to send across. Ended up being longer than expected (!)

[@PeLuRu4586]

Thank you for providing such a well-visualised explanation!!

[@CasualChemistry]

🙂 Thanks

[@derenjoy3r]

this is the good shit that i needed so badly, thx man

[@CasualChemistry]

No worries 🙂 Mean meaning to get something out there on this topic for a while

[@hasankoybas1079]

Very informative, excellent!

[@CasualChemistry]

🙂 Glad you enjoyed

[@geff9115]

Wonderful! Extraodinary! You really understand chemistry! Too often people thinks it's Always " by Heart"

[@CasualChemistry]

🙂 Thanks. Definitely one of my motivations for starting this channel is to play around with techniques and models to show memorisation isn’t the best approach to the subject. Unfortunately a lot of teachers encourage by-heart learning for organic chemistry but it hinders getting to the underlying principles.

[@geff9115]

@@CasualChemistry if i had a chemist professor as you... On France WE have the same issues. Some awsome teacher teaches us how tro thinks and proceed ans other feeds us with hundred of reactions and expects students to know everything

[@CasualChemistry]

@geff9115 probably how they learnt it themselves and just assuming that’s the best method. That’s a shame. Organic chem is more like maths I think - learn the methods well and you can solve more things

[@triklettriklerbu1592]

Hello, I have a question at 3:18 , how do you visualise and draw the bonds the way you do? I try so hard to do it and i cant understand which bond should be a wedged bond or a hashed bond. Another example is 7:50. Do you have any advice?

[@CasualChemistry]

Sorry for slow reply - I was busy finishing my dissertation. Back on to the videos now 🙂 I’m afraid there’s not an easy answer here other than a lot of practice on my part. I find it easiest to try and get as much of the molecule as possible in the plane of the paper - and definitely keep all the reaction arrows in the plane too else the 3D gets messy. Playing with a tetrahedron model can be a good idea too so you can visualise that important shape in several ways. Eg both like a pyramid but also like a triangle with a pointy out bit from one perspective. And from another perspective like two lines joining two atoms, one behind the other, at right angles.

[@UniCorneliusfan21]

Something that I never touched on Thanks man, I really did need that, although I don’t know if I have much motivation to get through it but I will try I suppose

[@CasualChemistry]

🙂 A topic I wanted to make sure was out there on KZbin for people as I see it getting muddled a fair bit when teaching

[@chemistrycapital]

Love the thumbnail

[@CasualChemistry]

Seemed appropriate for the 1980s-themed chemistry 🙂

[@Reaboian]

you guys are not good content creator, but GREAT content creator

[@CasualChemistry]

🙂 Thanks!

[@jamesduncan6902]

Doesn't the oxygen of the carbonyl on the oxazolidinone also co-ordinate to the metal centre making the dipole moments the same for the enolate and the carbonyl of the oxazolidinone? Why does the opposition of dipole moments outweigh the potential for additional co-ordination to the metal centre?

[@jamesduncan6902]

I guess it depends on the metal...

[@CasualChemistry]

Absolutely the right idea - it does depend on the metal. I’m going to revisit this in my next video. In this case Li is too small to do the 3-way chelation you mention. Boron with two alkyl ligands has no space left to do it either. But when you start branching into using transition metals or later p block elements, there’s a few other things that you can do including this 3-way chelation.

[@petevenuti7355]

Anyone got a 3D animation of this to help me connect the 2D diagram to the 3D shape?

[@CasualChemistry]

I’m not aware of a specific one but I could have a go at making one as a Short video - though my animating skills aren’t great but I could add some extra steps showing rotations/other models to help? Do you have a timestamp for a bit that you found particularly tricky for me to focus on?

[@petevenuti7355]

@@CasualChemistry all those curvy arrows this coming from this way, or get that from that and I'm only seeing a 2d plane... But I know pi bonds are sticking up and downish , right, or are they coming out of the page from the plane you wrote the arrows on? There's a lot of new stuff, 45 years since I was in school. My college level is high school stuff now ....

[@UniCorneliusfan21]

For me I usually see carbon skeleton structures and usually use that to rationalise diastereoselectivity and enantioselectivity, such as on cyclopentenone conjugate additions maybe, but yes you do need to understand 3d structures to be able to rationalise diastereoselectivity on some other reactions, particularly pericyclic reactions. An example would be the claisen reaction, which could pass through a chair or boat like transition state depending on the substrate which the chair and boat TS lead to different diastereoners Use a modelling kit to visualise I guess, I’ve never got the time to use my own one

[@6a7m]

me, a high school student, watching this: :0

[@CasualChemistry]

🙂 Spoilers for quite a way after high school