Chapter 15

Question 1

Are reactions favored when products are aromatic?

Answer 1

Yes

Question 2

When happens when X2 and FeX3 (X=halogen) reacts with a benzene molecule? Can also be AlCl3,FeCl3, or FeBr3.

Answer 2

X replaces a hydrogen. The location of the halogen is determined by ortho/para or meta directing groups

Question 3

What happens when HNO3 and H2SO4 reacts with a benzene molecule? Can also be XNO2 and FeCL3 or AlCl3.

Answer 3

NO2 replaces a hydrogen. The location is determined by directing groups.

Question 4

What happens when SO3 and H2SO4 reacts with a benzene molecule?

Answer 4

SO3H replaces a hydrogen. The location is determined by directing groups. Use concentrated/fuming sulfuric acid to sulfonate and use dilute sulfuric acid and steam to desulfonate

Question 5

What happens when RX and AlCl3 (or FeCl3) reacts with a benzene ring?

Answer 5

R replaces a hydrogen, carbocation rearrangement possible with most stable product only. (iso-butyl will rearrange to test-butyl)

Question 6

What happens when RCOCl or (CH3CO)2O and AlCl3 reacts with a benzene ring? (RCOCl is aldehyde with Cl replacing the H)

Answer 6

C(=O)R replaces a hydrogen

Question 7

What is the general mechanism for Electrophilic substitution?

Answer 7

Benzene-H + EA -> Benzene-E + H-A. All the reactions in this chapter are electrophilic substitution.

Question 8

What are electron-withdrawing groups?

Answer 8

Make the ring less nucleophilic and slow reactions. Function as Meta directors.

Question 9

What are electron-donating groups?

Answer 9

Make the ring more nucleophilic and speed up reactions. Function as Ortho/Para directors

Question 10

What are the common withdrawing/deactivating groups?

Answer 10

Nitro (NO2), Carbonyl (=O), Cyano (CN), CF3, Sulfonyl (SO3R), NR3

Question 11

What are the common donating/activating groups?

Answer 11

Hydroxyl (OH), Alkoxy (OR), Amino (NH2), Alkyl (-R)

Question 12

Which substituents are Ortho-Para directors?

Answer 12

Activating/Donating groups and halogens.

Question 13

Which substituents are Meta-directors?

Answer 13

Withdrawing/Deactivating groups

Question 14

Which dominates, Ortho/Para directors or Meta?

Answer 14

Ortho/Para

Question 15

If a benzene ring has two O/P groups or two M groups, which one applies?

Answer 15

The most activating one

Question 16

What happens when hot concentrated KMnO4 reacts with Ph-CH2-R?

Answer 16

->Ph-C=O,-OH

Question 17

What happens when hot concentrated KMnO4 reacts with Ph-CH3?

Answer 17

->Ph-C=O,-OH

Question 18

What happens when hot concentrated KMnO4 reacts with CH3-Ph-CH3?

Answer 18

->Ph-COOH,-COOH

Question 19

Order these from most donating to most withdrawing:
((-RX3/-NO2/-N+R3))

((-NH2/-NR2/-OH/-O-))

((RC(=O)OR/-R(=O)R/-R(=O)OH/-RC≣N/-SO3H))

((-R))

((-X))

((-OR)

Answer 19

1) -NH2/-NR2/-OH/-O-
2) -OR
3) -R (including phenyls)
4) -X
5) -RC(=O)OR/-R(=O)R/-R(=O)H/-RC(=O)OH/-RC≣N/-SO3H
6) -RX3/-NO2/-N+R3

Question 20

If you want to add an R group to a benzene and avoid rearrangements, how would you do it?

Answer 20

Friedel-Crafts acylation (RCOCl) followed by clemmensen reduction (Zn(Hg) and HCl)

Question 21

How do bulky substituents affect substitution reactions?

Answer 21

They prevent interactions with adjacent carbons

Question 22

How can you monobrominate a benzene ring with an amine group?

Answer 22

Convert the amine (NH2) to an amide (NHCOCH3) by FC acylation, then add acid to remove the protecting group. (back into NH2). Will be Ortho/Para