Chapter 17

Question 1

Electrophilic Aromatic Substitution (_______)

Answer 1

EAS

Question 2

EAS: substitution of an _______ for a proton on an aromatic ring

Answer 2

electrophile

Question 3

In EAS what step is the RDS?

Answer 3

step 1
- going from A to NA

Question 4

EAS require very high Ea which requires _______

Answer 4

harsh conditions
- heat or acid catalyst

Question 5

What are the 2 steps in all electrophilic aromatic substitution reactions?

Answer 5

1) form E+
2) attack E+

Question 6

What is the catalyst in the nitration of benzene reaction?

Answer 6

Sulfuric acid (H2SO4)

Question 7

Reduction of aromatic NO2 = best method for adding an ______ group

Answer 7

amino
- adds nitro and then turns into amino

Question 8

What are the acceptable reagents for reducing an aromatic NO2

Answer 8

Zn, Sn, or Fe
+ HCl (aq)
- turns nitro into amino

Question 9

The methyl substituent on an aromatic ring is an _______ group

Answer 9

activator

Question 10

General rule #1: if the substituent on the benene can stablize the carbocation intermediate (3°>2°>1°) that forms upon electrophilic addition, then it is termed _______-director

Answer 10

o,p
ortho, para

Question 11

What are the two ways that groups can stabilize intermediates?

Answer 11

1) R-groups can stablize C+ through EDG inductive capabilities (hyperconjugation)
2) groups that contain an atom with a lone pair can stabilize by donating electrons via resonance

Question 12

Oxygen is a strong electronegative group, but it donates electron density to stabilize the transition state = _______, which makes it an _______

Answer 12

resonance
activator
(resonance EDG characteristic wins over its EDG characteristic)

Question 13

The nitro substituent is a _______ group

Answer 13

deactivator

Question 14

General Rule #2: if the substituent on the benzene ring contains an atom that has a + or δ+, it is a _______-director

Answer 14

meta
- avoids + and + next to each other

Question 15

Halogen substituents are _______ groups and _______- directors

Answer 15

deactivator
o,p

Question 16

If the substituent on the ring is electron donating, the ortho and para positions will be _______

Answer 16

activated
- EDG activates

Question 17

If the substituent on the ring is electron withdrawing, the ortho and para positions will be _______

Answer 17

deactivated
- EWG deactivates

Question 18

If focus atom:
1) is an alkyl group (R-group) = _______-director
2) Has a lone pair = _______-director
3) has a + or δ+ = _______-director

Answer 18

1) o,p
2) o,p
3) m
- 1 and 2 are activating except halogens
- 3 is deactivating

Question 19

When the directing effects of the 2 or more groups _______ each other, you’ll get 99% of the product

Answer 19

reinforce

Question 20

Large substituents/electrophiles want to avoid steric interactions leading to the preference of the _______ product

Answer 20

para

Question 21

If the directors conflict, the _______ activating group determines the final regiochemistry

Answer 21

more

Question 22

When 2 rings conflict, add new group to the _______ activated ring system

Answer 22

most

Question 23

What are the reagents for halogenation of benzene (Br)

Answer 23

Br2, FeBr3

Question 24

What are the reagents for halogenation of benzene (Cl)

Answer 24

Cl2, and AlCl3 or FeCl3

Question 25

What are the reagents for halogenation of benzene (I)

Answer 25

I2, HNO3

Question 26

When highly activated aromatic rings (**phenol, aniline, etc**) are used, _______ substitutions may often result. Must show the # of moles used!

Answer 26

multiple

Question 27

What is the mild base needed to neutralize acid in halogenation of benzene?

Answer 27

NaHCO3

Question 28

Halogenation of benzene reactions with multiple moles used are _______ reactions

Answer 28

stepwise 1) para 2) ortho 3) 2nd ortho

Question 29

What is another name for the reagents that add SO3H to benzene?

Answer 29

fuming sulfuric acid - SO3, H2SO4

Question 30

What is another name for the reagents that remove SO3H to benzene?

Answer 30

steam - H2SO4, H2O, Δ

Question 31

In Fiedel-crafts alkylation, the limitations are: 1) the product is ________ reactive than the starting material 2) It doesn't work with compounds possessing moderately or strongly _______ substituents 3) _______ rearrangements can occur

Answer 31

1) more 2) deactivating - m-directors 3) C+

Question 32

What are the 2 other ways for the E+ to be formed in Friedel-Craft alkylation?

Answer 32

1) add acid to an alkene (H2SO4 or HF) 2) treat alcohols with lewis base (BF3)

Question 33

What were 2 ways Suzuki's graduate work improved Friedel-craft alkylation?

Answer 33

1) solved strong acid problem 2) solved the deactivating substituents problem

Question 34

Friedel-Crafts acylation is quite sensitive to _______, so will add the "_______" position

Answer 34

sterics para

Question 35

Friedel-Crafts acylation, there are no _______ rearrangements

Answer 35

C+

Question 36

There are no _______ acylations, as the acyl group is deactivating so the product is _______ reactive than the starting material

Answer 36

multiple less

Question 37

In Friedel-Crafts acylation, the product complex must be hydrolyzed by _______ to release the free acyl benzene

Answer 37

water - see 17-11 for ex

Question 38

If Friedel-Crafts acylation is intramolecular, there is addition at the _______ position

Answer 38

ortho

Question 39

The Clemmensen reduction allows for _______

Answer 39

reduction of acylbenzene to alkylbenzene - removes C=O

Question 40

The Gatterman-Koch synthesis allows ________ to be added to a benzene

Answer 40

aldehyde

Question 41

What are the reagents for Gatterman-Koch synthesis?

Answer 41

1) CO 2) HCl 3) AlCl3 4) CuCl

Question 42

What are the two Nucleophilic Aromatic Substitution reactions?

Answer 42

1) Addition-Elimination (EWG) 2) Elimination-Addition (benzyne)

Question 43

For **Addition-Elimination** reactions, the original molecule must have an _______ either **ortho or para** to the halide LG

Answer 43

EWG

Question 44

In addition-elimination reactions, the leaving group step is not the ______, but the LG does stabilize the intermediate

Answer 44

rds - rds is addition of nuc to electrophile

Question 45

The rate of an addition-elimination reaction is based on _______ of LG

Answer 45

EN Fast: F>Cl>Br>I :Slow

Question 46

What are the possible nucleophiles for addition-elimination reactions? (3)

Answer 46

1) NH3 2) OH 3) OR

Question 47

Elimination-Addition requires very strong _______ conditions, or a _______ and high heat

Answer 47

basic base

Question 48

What are the possible strong bases used in elimination-addition reactions?

Answer 48

NaNH2 NaNR2

Question 49

What are the possible bases coupled with heat used in elimination-addition reactions?

Answer 49

NaOH ROH **needs heat**

Question 50

Elimination-Addition reactions form _______ which is very reactive and usually results in the formation of 2 products

Answer 50

benzyne - forms 2 products 50:50 ratio

Question 51

What are the reagents for a birch reduction reaction?

Answer 51

Na or Li +NH3 (l), ROH

Question 52

A birch reduction reaction that contains an **EDG** will result in what?

Answer 52

double bonds **on** the C with the substituent

Question 53

A birch reduction reaction that contains an **EWG** will result in what?

Answer 53

Double bonds that **avoid** the C with the substituent

Question 54

Strong oxidation agents such as KMnO4 and Na2Cr2O7 will undergo side-chain _______ when reacted with a substituted benzene

Answer 54

oxidation - turns any CH connected to or conjugated to a benzene into carboxylic acid - See 17-15 for explanation

Question 55

Oxidation of phenols to quinones are done by _______ (reagents)

Answer 55

Na2Cr2O7, H2SO4