FINAL

Question 1

Which reactions prefer strong bases or nucleophiles?

Answer 1

bimolecular (SN2 or E2)

Question 2

Which reactions prefer weak bases or nucleophiles?

Answer 2

unimolecular (SN1 or E1)

Question 3

What makes something a strong nucleophile?

Answer 3

Negative charge, larger atoms, less electronegativity

Question 4

What makes something a weak nucleophile?

Answer 4

Neutral or weakly charged, small, more electronegative

Question 5

What are examples of strong nucleophiles

Answer 5

I-, S2-, CN-

Question 6

What are examples of weak nucleophiles

Answer 6

Water, NH3, alcohols (ROH)

Question 7

When are bases bad nucleophiles

Answer 7

When they are bulky or hindered

Question 8

When are nucleophiles bad bases

Answer 8

If they are highly polarizable (low electronegativity, larger atomic radius, negative charge)

Question 9

What type of reaction(s) favors heat

Answer 9

Eliminations (E1, E2)

Question 10

Polar aprotic solvents favor which reactions?

Answer 10

SN2/E2

Question 11

If we have a bulky base as our nucleophile, which reaction can we rule out?

Answer 11

SN2

Question 12

For a primary alkyl halide reacting with a non-bulky base, which reaction will occur?

Answer 12

SN2

Question 13

If the nucleophile is a strong bulky base, which reaction will occur

Answer 13

E2

Question 14

For primary and secondary alkyl halides, good nucleophiles that are weakly basic will favor which reaction(s)?

Answer 14

SN2

Question 15

For tertiary alkyl halides, weak nucleophiles/bases favor which reaction(s)?

Answer 15

SN1/E1

Question 16

Describe the flowchart for primary alkyl halides

Answer 16

SN2 unless strong base but weak nucleophile (aka bulky base)

Question 17

Describe the flowchart for secondary alkyl halides

Answer 17

Weak nuc/base means SN1. Strong nuc/base favor SN2/E2. In this case, weak base but strong nu indicates SN2, while strong base of any kind (whether or not strong nuc) indicates E2.

Question 18

Describe the flowchart for primary alkyl halides

Answer 18

SN2 unless bulky base

Question 19

Polar aprotic solvents favor which kinds of reactions

Answer 19

Polar aprotic solvents favor SN2 and E2 reactions

Question 20

Polar protic solvents favor which kinds of reactions

Answer 20

Polar protic solvents favor SN1 and E1 reactions

Question 21

Which kinds of nucleophiles favor subsitution?

Answer 21

Strong nucleophiles

Question 22

CN- is a strong or weak nucleophile?

Answer 22

Strong

Question 23

N3- is a strong or weak nucleophile

Answer 23

Strong

Question 24

Strong bulky bases favor what kinds of reactions?

Answer 24

Elimination

Question 25

What are some weak bases/nucleophiles favoring E1/SN1

Answer 25

Water, NH3, CH3OH

Question 26

SH- is what kinds of nucleophile

Answer 26

Strong nucleophile

Question 27

SR- is what kind of nucleophile

Answer 27

Strong nucleophile

Question 28

I- is what kind of nucleophile

Answer 28

Strong nucleophile

Question 29

NaOEt is what kind of base. Which kind of reaction does it favor?

Answer 29

Strong base favoring E2

Question 30

ROH favors which reactions

Answer 30

SN2 and E2

Question 31

SN2 requires a strong ______

Answer 31

A strong base

Question 32

E2 requires a strong _____, but not necessarily a strong ______

Answer 32

nucleophile, base

Question 33

In polar aprotic solvents, the best nucleophile order for halogens is going ___ to ____ of group 7. Why?

Answer 33

top to bottom. F is more reactive and wont be solvated bby any hydrogens that would be present in a polar protic solvent.

Question 34

In polar protic solvents, the best nucleophile order for halogens is going ___ to ____ of group 7

Answer 34

Bottom to top

Question 35

Methyls as substrates will yield which kinds of reactions

Answer 35

SN2

Question 36

Primary alkyl halides undergo which kinds of reactions.

Answer 36

SN2 UNLESS strong bulky base. In which case, E2 will occur

Question 37

Tertiary alkyl halides undergo which kinds of reactions?

Answer 37

E2 if there is a strong base, SN1, E1 otherwise.

Question 38

Secondary alkyl halides reacting with strong bases undergo what kind of reaction?

Answer 38

E2

Question 39

If there is a polar aprotic solvent, secondary alkyl halides likely undergo which reaction(s)?

Answer 39

SN2

Question 40

If there is a polar protic solvent, secondary alkyl halides likely undergo which reaction(s)?

Answer 40

SN1/E1

Question 41

What are some weak bases but strong nucleophiles?

Answer 41

Halides, RS-, RSH, H2S

Question 42

Bulky bases always favor _____

Answer 42

Elimination

Question 43

What are some basic nucleophiles

Answer 43

RNH2, RNH-, NH2, R---(triple bond), -OH, -R

Question 44

Basic nucleophiles favor which reaction(s)

Answer 44

E2 and SN2

Question 45

For basic non bulky nucleophiles, primary alkyl halides favor which reaction? What about secondary alkyl halides?

Answer 45

SN2 for primary, E2 for secondary

Question 46

What is the formula for formal charge?

Answer 46

of valence electrons - lone pairs - electrons shared in bonds/2 (aka number of connections)

Question 47

What are enantiomers

Answer 47

Non superimposable mirror images

Question 48

What are diastereomers

Answer 48

Non superimposable non mirror images

Question 49

What are meso compounds

Answer 49

Achiral compounds with stereocenters

Question 50

What is chirality

Answer 50

Not superimposable on mirror image

Question 51

What is achirality

Answer 51

Superimposable on mirror image

Question 52

What is the difference between constitutional and conformational isomers?

Answer 52

Constitutional isomers are structural isomers, they nave the same formula but different connectivity. Conformational isomers are isomers that exist because of rotation about a single bond (think newman projection)

Question 53

Which reactions undergo syn addition?

Answer 53

Hydroboration oxidation

Question 54

Which reactions undergo anti addition

Answer 54

X2, halohydrin synthesis, and oxymercuration (of oxymercuration reduction)

Question 55

Which reactions are non selective

Answer 55

H-X addition, acid catalyzed hydration, and reductiion (of oxymercuration reduction)

Question 56

Describe the stereochemistry of SN2

Answer 56

Inversion of stereochemistry

Question 57

Describe the stereochemistry of E2 reactions

Answer 57

Anti periplanar elimination. Trans product preferred

Question 58

Describe the stereochemistry of E1 reactions

Answer 58

Zaitsev product generally preferred. Trans alkene also preferred?

Question 59

Describe the stereochemistry of SN1 reactions

Answer 59

Typically a racemate (if reaction occurs at chiral center). Non selective addition.

Question 60

What is anti (in regards to newman projections)

Answer 60

The most stable staggered conformation. An energy minimum.

Question 61

What is gauche (in regards to newman projections)

Answer 61

Staggered, but not the most stable

Question 62

Eclipsing vs. Staggered

Answer 62

Staggered more ideal. Eclipsed are energy maxes.

Question 63

On cyclohexan chairs, of up and down, which one is dash and which one is wedge.

Answer 63

Up is wedge, down is dash.

Question 64

For cycloalkanes, what ring sizes are more stable?

Answer 64

Bigger rings are more stable. Cyclohexans are always most stable, cyclopental also very stable

Question 65

What are the three kinds of ring strain with cyclohexanes

Answer 65

Angle strain, torsional strain, and steric strain.

Question 66

Strong base but weak nucleophile will yield which reaction?

Answer 66

E2

Question 67

Strong base and strong nucleophile rules out which kind of reactions

Answer 67

First order (E1/SN1)

Question 68

Weak base but strong nucleophile yields which reactions and when?

Answer 68

SN2 if primary or secondary substrate, SN1 if tertiary substrate