How E2 Elimination Reactions Work (Animation) | Mechanism & Orbitals | Organic Chemistry

👀 This video explains E2 eliminations: basics of geometries, orbitals, selectivities...
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total-synthesis.com
00:00 E2 elimination basics and orbitals
01:14 Ask yourself these questions
01:31 Level 1: 2-Bromobutane elimination and stereoselectivity
02:46 Level 2: Kinetic isotope effects and stereospecificity
04:35 Level 3: Cyclic substrates and A-values
06:25 Level 4: Peterson olefination and Brook rearrangement
The bimolecular elimination (E2 elimination) reaction is a cornerstone of organic chemistry, particularly for synthesis of alkenes. In the E2 mechanism, a base abstracts a proton (H+) from a carbon adjacent to an sp3-hybridized carbon, which is bonded to a leaving group. Simultaneous expulsion of the leaving group, forms a double bond (alkene) - with a concerted mechanism (deprotonation and and leaving group departure occur in a single step). This contrasts with the E1 elimination mechanism, where the leaving group's departure is the rate-determining step and occurs before the deprotonation step.
Some recommended books on organic synthesis:
- Clayden, Greeves, Warren; Organic Chemistry (basic organic chemistry knowledge)
- Wyatt, Warren; Organic Synthesis: The Disconnection Approach (excellent introduction to retrosynthesis)
- Kurti, Czako; Strategic Applications of Named Reactions in Organic Synthesis (extensive toolkit of functional group reactions and applications thereof with common conditions)
- Nicolaou; Classics in Total Synthesis 1-3 (the ultimate total synthesis trilogy)
- Nicolaou; Molecules That Changed the World (the world's most important molecules and their impact on everyday life)
- Carreira, Kvaerno; Classics in Stereoselective Synthesis (compilation of the groundbreaking methods of stereoselective synthesis and application to synthesis of stereochemically complex structures)

[@totalsynthesis]

Hello there, thanks for watching! Our next few videos will focus on more complicated molecules and deeper chemistry - but let me know if would like to see more of these 'basic' videos in future! Thanks to all my supporters!
www.patreon.com/totalsynthesis; instagram.com/totalsynthesis_official/

[@ommhatre3645]

Underrated channel and Great videos! We want more such videos that teach reaction mechanisms. It would be great if you cover all types of mechanisms. If possible add animations as well 😊

[@totalsynthesis]

Thank you!

[@gabrielalx]

very nice video, you should try if it's possible to show the orbital interactions (like the bonding/antibonding/lone pair orbitals) that would help a lot of students vizualise what's really happening. Also you could maybe do a video on frontier molecular orbitals of conjugated systems (conjugated unsaturated ketones, conjugated polyenes, enolates / extended enolates etc.) , that would be really cool!

[@totalsynthesis]

Thanks, great suggestions!

[@jonathana.1802]

Love the visuals reprensentation it's a really great to learn at understand the reaction. Please make more of them haha

[@totalsynthesis]

Thanks for the nice feedback and comment!

[@matejnastran9586]

Nice video, I prefer your style to every other theoretical chemistry youtuber, but I think these basics are well covered by others and you should focus on more advanced topics.

[@totalsynthesis]

Thanks for watching and the comment! You can look forward to more advanced topics :)

[@amanitaocreata4401]

They didn't cover that Si stuff in my book, thanks!

[@totalsynthesis]

Thanks for watching!

[@user-uf8gu9ne1g]

But why is resonance so effective in predicting almost all types of reactions? Continue with NBMOs and resonance-type heuristic MO approximations!

[@zachlerdahl8115]

I think it would be really cool if you could animate the bonds forming and unforming when these molecules react with each other. Seeing that happen in 3D space would make this sort of stuff very intuitive. However, that does sound very time consuming. Maybe try just animating 1 reaction forming somewhere in the video. Love this video by the way! Thank you so much!

[@totalsynthesis]

Fully agree, unfortunately I think that would require me to use 10h in Blender (likely more as I never used it) to animate the actual bonding. I hope this is a decent start to visualize things better :)

[@zachlerdahl8115]

@@totalsynthesis Gotcha, yeah that makes sense. Still absolutely great work! I love it!

[@chasharris1976]

Interesting

[@SharpAssKnittingNeedles]

Very nicely explained! Skilled lecturers who make it interesting and understandable are so rare 😢 I was lucky to have an instructor like you who made ochem fun and a joy to study. Makes me so sad when people say they hate chemistry cuz they had a shitty instructor

[@totalsynthesis]

Thanks so much!! And nice name lol

[@SharpAssKnittingNeedles]

@@totalsynthesis and thank you too! Would love to make you a beanie or something covered in hexagons cuz they work as nicely in a knit fabric as well as they do in organic compounds! But shipping to the EU would prolly be prohibitive 😔 in the US here and huge fan of all your videos bro!

[@totalsynthesis]

@@SharpAssKnittingNeedles Hahahah, appreciate it!

[@OpiatedBliss]

5:46 wondering if the boat configuration would be significant here, since it would have tBu-equatorial. Boat conformations are usually higher energy but this case may be an exception?

[@totalsynthesis]

Interesting thought, but because the normal boat is 6kcal/mol higher than chair, Im not sure if the axial tBu would be enough to override

[@OpiatedBliss]

cool

[@triple_gem_shining]

Sweet