Chapter 5: 5.8 The E2 Reaction

Question 1

Describe:

E2 Reactions

Answer 1

Bimolecular
* Two species are present in the rate equation
* Changing the concentration of either species changes the rate

Question 2

State:

The etymology of E2 Reactions

Answer 2

Elimination Bimolecular (2) Reactions

Question 3

State:

Rate equation for E2 Reactions

Answer 3

Rate = k [substrate] [base]

Question 4

What structural requirements do E2 reactions occur under?

Answer 4

Occur between a strong base (NaOEt) and an electrophile with little steric hinderance (Me-I)

Question 5

What process occurs in an E2 Reaction?

Answer 5

Direct deprotonation and formation of the alkene in a single step

Question 6

A strong base is usually…

Answer 6

Negatively charged
* Watch for sodium and potassium

Question 7

In E2 reactions:

The hydrogen atom that is being deprotonated and the leaving group have to be what from each other?

Answer 7

Anti-periplanar (180 degrees apart) from each other

Question 8

What should you draw to predict if a reaction will occur/what the product will be like in E2 reactions?

Answer 8

Newman projection or chair conformation

Question 9

What can E2 Reactions be used to make?

Answer 9

Alkynes

Question 10

E2 reactions with what compounds can create alkynes?

Answer 10

1. Vincinal dihlaides
2. Geminal dihalides

Question 11

What is the most common base for an E2 reaction creating alkynes?

Answer 11

Sodium amide (NaNH2)

Question 12

True or False:

NaNH2 is best used to make internal alkynes

Answer 12

True, as it is strong enough base to deprotonate terminal alkynes

Question 13

Describe:

E2 Reaction Mechanism

Answer 13

Happens in a single step via a crowded transition state that requires anti-periplanar geometry of the leaving group and hydrogen atom