DAT Ochem Substitution and Elimination

Question 1

an electron-rich species that tends to donate electron density

Answer 1

nucleophile

Question 2

an electron-poor species or compound

Answer 2

electrophile

Question 3

Nucleophile strength increases from…. on pd table

Answer 3

right to left

Question 4

increase in nucleophilicity is due to decreasing

Answer 4

e/n

Question 5

nucleophile strength increases down a group in what kind of solvent

Answer 5

polar protic

Question 6

A larger
atomic radius results in

Answer 6

more reactive nucelophile

Question 7

nucleophilicity decreases down a group in what kind of solvent

Answer 7

polar aprotic

Question 8

In polar aprotic solvents, nucleophilicity parallels….

Answer 8

basicity

Question 9

Basicity decreases

Answer 9

down a group

Question 10

Both substitution and elimination reactions involve the

Answer 10

loss of LG

Question 11

nucleophile attacks an electrophile and kicks out a leaving group… what kind of rxn

Answer 11

SN2

Question 12

nucleophilic attack and loss of a leaving group occur in the same step.

Answer 12

concerted

Question 13

rate law for sn2

Answer 13

k(nuc)(elec)

Question 14

if a nucleophile attacks a chiral center, what happens to stereochemistry …. SN2

Answer 14

inverted

Question 15

consists of separate steps and therefore is not concerted.

Answer 15

Sn1

Question 16

first step of an SN1

Answer 16

carbocation intermediate formation via the loss of a leaving group.

Question 17

what is the rate limiting step of an SN1 rxn

Answer 17

carbocation intermediate formation via the loss of a leaving group.

Question 18

final step of SN1

Answer 18

nucleophilic attack of the carbocation.

Question 19

SN1 can only occur with what kind of substrates

Answer 19

secondary and tertiary

Question 20

rate law for SN1

Answer 20

k(electrophile)

Question 21

Carbocations
can be stabilized by neighboring alkyl groups bonds via

Answer 21

hyperconjugation

Question 22

what is the least stable carbocation rearrangement

Answer 22

vinyl

Question 23

what is next to least stable carbocation rearrangement

Answer 23

phenyl

Question 24

what is more stable carbocation, methyl or primary

Answer 24

primary

Question 25

what is more stable methyl or phenyl

Answer 25

methyl

Question 26

what is most stable carbocation arrangement

Answer 26

benzyl

Question 27

what is next to most stable carbocation rearrangement

Answer 27

allyl

Question 28

are SN1 reactions stereospecific

Answer 28

no

Question 29

more substituted alkene,

Answer 29

zaitsev product

Question 30

less substituted alkene

Answer 30

hofman

Question 31

what product is favored if the base is large and sterically hindered.

Answer 31

hofman

Question 32

what product is favored When a non-sterically hindered base is used

Answer 32

zaitsev

Question 33

are E2 rxn concerted

Answer 33

yes

Question 34

E2 rate law

Answer 34

k(base)(substrate)

Question 35

In an E2 reaction, the leaving group and the beta proton must be

Answer 35

antiperiplanar

Question 36

For cyclohexane, E2 reactions only occur if the leaving group and beta proton are

Answer 36

on adjacent axial positions and are anti-periplanar to one another:

Question 37

what version of alkene is preferred to be formed for an E2 rxn

Answer 37

E alkene

Question 38

If the substrate has only one proton on the relevant beta carbon, only... (e2)

Answer 38

stereoisomer is possible

Question 39

E1 rxn rate law

Answer 39

k(substrate)

Question 40

E1 reactions occur using what kind of bases

Answer 40

weak

Question 41

examples of weak bases

Answer 41

h2o or alcohol

Question 42

strong bases favor...

Answer 42

e2 rxns over e1

Question 43

Heat can be added to the reaction to ensure that the

Answer 43

E1 product is favored over the SN1 product.

Question 44

elimination of alcohols requires the use of

Answer 44

concentrated acid and heat

Question 45

what is always the major product of an acid catalyzed dehydration reaction.

Answer 45

Zaitsev product

Question 46

If the alcohol is primary, what type of rxn will occur

Answer 46

e2

Question 47

The first step of acid catalyzed dehydration is...

Answer 47

protonation of the hydroxyl group to make it good lg

Question 48

does not occur with a tertiary substrate,

Answer 48

SN2

Question 49

what kind of rxns will a primary subs not work with

Answer 49

SN1, E1

Question 50

which are possible with a secondary substrate,

Answer 50

all 4 mechanism

Question 51

negatively charged molecule is

Answer 51

reactive, strong base/nucleophile

Question 52

If the molecule is neutral and unreactive, it is a

Answer 52

weak base/nucleophile

Question 53

A strong base/nucleophile will favor

Answer 53

SN2, E2

Question 54

a weak base/ nucleophile will favor

Answer 54

SN1, E1

Question 55

A sterically hindered molecule will almost exclusively act as a

Answer 55

base

Question 56

A polar protic solvent favors

Answer 56

E2

Question 57

a polar aprotic solvent favors

Answer 57

SN2

Question 58

At low temperatures, what is more likely

Answer 58

nucleophile subsititution

Question 59

at high temps, what is more likely

Answer 59

elimination

Question 60

Br-, I-, Cl-, H2S, RS-, HS-

Answer 60

non basic nucelphile

Question 61

primary substrate, nonbasic nucleopuile

Answer 61

SN2

Question 62

secondary subs, polar aprotic solv, nonbasic nuc

Answer 62

SN2

Question 63

secondary subs, polar protic, nonbasic nuc

Answer 63

SN1

Question 64

tertiary subs, non basic nucleophile

Answer 64

SN1

Question 65

t-buOK, DBU, DBN, Diisopropylethylamine, Triethylamine, LDA, NaH

Answer 65

non nucleophilc base

Question 66

what kind of rxn is favored for all non nucleophilc bases

Answer 66

e2

Question 67

RO-: HO-, MeO-, EtO-

Answer 67

strong nuc, strong base

Question 68

strong nuc, strong base, primary OR secondary, polar aprotic

Answer 68

SN2

Question 69

strong nuc, strong base, primary OR secondary, polar protic

Answer 69

E2

Question 70

strong nuc, strong base, tertiary

Answer 70

E2 only

Question 71

ROH: HOH, MeOH, EtOH

Answer 71

weak nuc, weak base