Question : destroyer roadmap #3 (picture)

[I Brush My Teeth]

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Can someone tell me why these two reactions yield different products?

I thought it was just a simple E2 where a double bond would be made at the most stable carbon

 

[WTN13]

What is the reaction?

 

[BeaverLover]

The reactant in the above reaction is a bulky base, forming a anti-Zaitzev rule...I think

 

[DAT Destroyer]

Can someone tell me why these two reactions yield different products?

I thought it was just a simple E2 where a double bond would be made at the most stable carbon

The are indeed BOTH E2 reactions. Look closely at the employed base. If C2H5O-/C2H5OH is used we do a Zaitsev elimination whereby the most substituted alkene is formed. In the reaction going at the top, a larger, sterically hindered base was used, We used Sodium t-Butoxide...this reagent gave E2 Hoffmann, whereby the less substituted alkene was formed. For further clarity, see the David Klein text book which gives many more examples of this VITAL reaction series.

Hope this helps

Dr. Jim Romano

 

[ThunderSplash]

A big base can't get to the "inner" H so it grabs the H the outside and makes less substituted alkene. A small base can grab the "inner H" and makes most substituted alkene. Look at the mechanism and it will make sense. It confused me too!

 

[I Brush My Teeth]

Appreciate it! After so much studying, the little things are falling out of my brain 🙁 haha 2 weeks left!

 

[DAT Destroyer]

Appreciate it! After so much studying, the little things are falling out of my brain 🙁 haha 2 weeks left!

When the little things fall out pick them up and put them back in!🙂

😀Keep going! The finish line is in sight!

Nancy

 

[ThunderSplash]

Appreciate it! After so much studying, the little things are falling out of my brain 🙁 haha 2 weeks left!

I used my last week to take 2 full lengths and review Destroyer's Roadmaps (if you know these you're golden) and a sheet where I kept extra Biology stuff that was giving me trouble. You're in the home stretch! Stay focused.

 

[WTN13]

What is the reaction?

Woops, didn't see the attachement. They got it covered though!