4. Elimination

Question 1

Steps of E1 mechanism

Answer 1

1) loss of leaving group, 2) base takes proton, 3) alkene product. Depends on conc of substrate; R = k[substrate]

Question 2

What makes a good leaving group?

Answer 2

lower pKa, weak bases, have to be stable once they leave molec

Question 3

Some products can be disubstituted for trisubstituted. Which one is more stable? What do you call a more substituted/stable product?

Answer 3

Trisubstituted; Zaitsev product

Question 4

Some products may be cis or trans alkene. Which one favors?

Answer 4

Depends on side groups. If there are 2 bulky groups, they rather be in trans

Question 5

How do you know how much substituted?

Answer 5

Mono = double bond bonds to 1 alkyl, di = double bond bonds to 2 alkyls, and tri = double bond bonds to 3 alkyls

Question 6

Steps of E2 mechanism

Answer 6

1) Base attacks H from a C, 2) double bond forms, 3) alkene product and HB; all this happens at same time. Bimolecular, k=[substrate][B]

Question 7

What happens if you have a bulky base for E2?

Answer 7

They prefer less bulky H’s and less substituted alkene will be the major product => Hofmann product

Question 8

Zaitsev product vs Hofmann product

Answer 8

Generally: more substituted and stable alkene product vs less substituted alkene product

Question 9

Major product vs minor product

Answer 9

More favored product vs less favored product; happens in E1; depends on how bulky base is

Question 10

Nucleophilicity trend on periodic table

Answer 10

Inc down and left

Question 11

Is water a stronger or weaker nuc than hydroxide?

Answer 11

Weaker