7.5 E2 Reactions | Organic Chemistry

Chad breaks down everything you need to know about E2 Reactions. He starts with the concerted mechanism and the rate law showing the E2 reaction mechanism stereochemistry, how the beta hydrogen and the leaving group must be antiperiplanar when E2 elimination occurs. He introduces Zaitsev Rule (aka Saytzeff Rule), how it is most common in E2 reactions for the most substituted alkene possible to be the major product. He then shows that for some substrates with only one beta hydrogen only one specific stereoisomer may be possible for the product (either E or Z) and shows how to predict which one it is. Chad then explains that for E2 reactions involving cyclohexane the beta hydrogen and the leaving group must be trans-diaxial in order to be antiperiplanar and for the E2 mechanism to occur. He concludes the lesson by showing common exceptions to Zaitsev rule (Hofmann Elimination) such as when a bulky base (like t-butoxide) is used or when having a poor leaving group like fluorine.

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00:00 Lesson Introduction
00:52 E2 Reaction Mechanism and Zaitsev Rule
02:41 E2 Rate Law
03:41 E2 Reaction Stereochemistry - Antiperiplanar
08:43 E2 Reactions Stereochemistry - E vs Z Alkene Product
14:14 E2 Reactions with Cyclohexane
19:10 E2 with a Bulky Base (Hofmann Product)
22:44 E2 with a Bad Leaving Group (Hofmann Product)

[fritz]

Sir, don't stop with the vids. I am indebted.

[jessicaneamtu]

These last few videos have explained SN1, SN2, and E2 so well! Watching them in order has been especially helpful. Thank you!

[jamesthehogan]

Incredible series! Has helped me feel so much more confident for my O-Chem final :) You're amazing at explanations of these topics. Keep it up!

[hassanshah]

Hey Chad, Just wanna say Ive watched all of your o chem and gen chem vids and you have been my main source of studying for 3 semesters. Thank you so much and god bless you

[pffzmdl]

Not this prof is literally amazing I don’t know how I could thank you for all this

[rachelifolger]

Hi Chad! I have been following your videos since gen chem and they have been really helping me, my next chemistry course is biochemistry, are you planning on making videos on the subject? If yes that would be truly helpful!

[fritz]

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[dnews]

20:36 me after i eat too much taco bell

[hollyhele]

So thankful for these videos!! Thank you!

[sanyamsapra]

Thanks sir 👍👍🙏🏻😀 amazing video learned something new in this video 😀😀👍

[evelez]

Great videos. Thank you so much for your help!!

[karnmattu]

For the example at 8:50, when ur rotating the substituents is the rotation always in a certain clockwise fashion?

[courtneyjohnson]

First, thank you so much for your videos. Second, how did you find the chair conformation at 17:05? I've been struggling with those, do you have a video that explains them better?

[ouaridabenatia]

I don't say this lightly- I love you.

[stephenmarvin]

Hey! Wouldn't a build-up of a negative charge on the beta carbon repulse the oxygen that's trying to bind to it? I'm unsure if I understand the reasoning behind the E2 w/bad leaving group's mechanics.

[ayianaaa]

Maybe I missed it, but why did you show the chair configurations when explaining out the example with the cyclohexane? I didn't understand the connection.

[jympuwi]

25:28 what do you mean by kinetic product? Its the fastest to form

[ufcbrotha]

does anyone know if these are the same videos that are included in his 'premium' on the website? want to sign up, but if these are the same vids I'm going with the standard $90 vs the $180. Thanks

[donelleaguayo]

For the last problem (with fluorine as a bad leaving group), will you still form the Zaitsev product with a double bond between the secondary and alpha carbons? I get confused when determining how many products will be formed.