Chapter 9.6: Mechanisms of β-Elimination

Question 1

What is the regiochemistry of a E1 reaction?

Answer 1

o Regiochemistry: Zaitsev’s Rule  most substituted alkene

Question 2

Describe the mechanism of an E2 reaction

Answer 2

 Take a proton away and simultaneously break a bond to give stable molecules or ions

Question 3

What is the stereochemistry of an E2 reaction?

Answer 3

o Stereochemistry: Determined by antiperiplanar transition state

Question 4

Define E2 reaction

Answer 4

a bimolecular β-elimination reaction

Question 5

Describe the E1 mechanism

Answer 5

 Step 1: Break a bond to give stable molecules or ions
• Results in carbocation intermediate
 Step 2: Take a proton away
• Proton transfer from the carbocation intermediate to the solvent gives the alkene

Question 6

What is a bimolecular β-elimination reaction?

Answer 6

E2 reaction

Question 7

What is a unimolecular β-elimination reaction?

Answer 7

E1 reaction

Question 8

Define E1 reaction

Answer 8

a unimolecular β-elimination reaction

Question 9

What is the regiochemistry of an E2 reaction?

Answer 9

o Regiochemistry: Zaitsev’s Rule  most stable/most substituted alkene