Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Organic Chemistry I > CHP 10 - 11 > Flashcards

CHP 10 - 11 Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What are the 3 steps in radical chain rxn mechanisms?

A
  1. Initiate
  2. Propagation (rxn)
  3. Terminate (radicals go away)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens in the initiation step of a radical chain mechanism?

A

homolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens in the propagation step of a radical chain mechanism?

A

Product always ends up in propagation step

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens in the termination step of a radical chain mechanism?

A

The radicals (terminate) go away

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Heterolysis?

A

The movement of 2 full electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is homolysis?

A

The movement of 1 electron at a time. Energy introduced into the system to create a radical. AKA homolytic bond cleavage when the bond breaks, each atom will add 1 electron.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name this overall reaction

A

Reaction of Radical: Halogenation of Alkanes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is there selectivity (differenced in reactivity) between Br and Cl?

A

Reaction Kinetics.
The rxn of Cl2 has exothermic intermediates
The rxn of Br2 has endothermic intermediates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How to predict the major product of the following reaction

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is N-bromosuccinimide (NBS) and N-chlorosuccinimideused (NBS) for?

A

NBS and NCS are specifically used for brominating and chloronating allylic/benzylic positions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What radical initiators can be used with NBS?

A

peroxides ROOR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Name this overall reaction

A

Halogenation at the allylic/benzylic position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name this overall transformation

A

Addition of radicals to Alkenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Properties of Addition of radicals to Alkenes

A
  1. Anti-Markov addition of H-Br
    1. Radicals do not rearrange ( remember carbocations do rearrange)
    2. Reaction does not work w/ HI or HCl
      Stereochemistry (50/50 mixture)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the initiation step of the radical chain reaction mechanism for Addition of radicals to Alkenes?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the propagation step of the radical chain reaction mechanism for Addition of radicals to Alkenes?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the termination step of the radical chain reaction mechanism for Addition of radicals to Alkenes?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the following examples?

A

Examples of stereochemistry in Addition of Radicals to Alkene mechanisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Solve this Addition of Radicals to Alkenes synthesis

A

What’s changed? New C-C bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the two organometallic compounds to know for this class?

A

organolithium (R-Li) and Grignard organomagnesium (RMgBr)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the reactivity of R-Li and RmgBr?

A

Carboanion Reactivity:
1. Very strong base
2. Strong nucleophile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Name this organometallic mechanism

A

R-Li
Conjugate acid is a stronger acid because pka is greater that 8 points so the rxn is R->P irreversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Name this organometallic mechanism

A

RMgBr Grinard

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What type of solvents should be used for R-Li and RMgBr reactions?

A

Anhydrous or “dry” solvents such as Et2O to avoid H2O ruining the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How does RMgBr react with epoxides?

A

RMgBr acts as a strong nucleophile (base)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the two main coupling reactions that we are learning?

A

Gilman- Organocuprates (CuLi) and Suzuki-Miyaura Reaction (B(OH)2 and Pd(0))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Name this coupling mechanism

A

Organocuprates
Gilman Reagent + alkyl halide=stitched compound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Name this coupling mechanism

A

Organocuprates
Gilman Reagent + alkyl halide=stitched compound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Name this coupling mechanism

A

Suzuki-Miyaura Reaction (B(OH)2 and Pd(0))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What type of reaction with B(OH)2 and Pd(0) always make?

A

coupling reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does this overall transformation represent?

A

General scheme for substitution nucleophilic 2nd order biomolecular (SN2) reactions. The overall reaction is in 2nd order and rate=k[Nu][R-L.G]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What does this overall transformation represent?

A

General scheme for substitution nucleophilic 2nd order biomolecular (SN2) reactions. The overall reaction is in 2nd order and rate=k[Nu][R-L.G]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Name this mechanism

A

SN2 mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

In SN2 reactions, how does attacking the backside of a leaving group change the stereochemistry?

A

We get an inversion of stereochemistry a the carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What does the rate of SN2 reactions depend on?

A

The class of L.G, sterics of beta carbon (carbon right next to the carbon with the alkyl halide), and L.G. ability to leave (weaker the better)
methyl» 1 > 2&raquo_space; 3 (tertiary cannot happen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the rate of leaving trend for L.G. in a SN2 rxn?

A
37
Q

Define Nucleophiles

A

Nucleophiles (electron rich substance that want to share electrons with a nucleus) are electron pair donors (Lewis base) and react with a nucleus (carbon nucleus)

38
Q

Define Electrophile

A

Electrophile (electron deficient willing to accept electrons) is an electron pair acceptor (Lewis acid)

39
Q

Define Leaving groups (L.G)

A

Leaving groups (L.G): typically stable ions or neutral species when they leave. Conjugate bases of strong acids (pKa<5)

40
Q

Strong nucleophiles go SN2. Compounds with negative charges are more nucleophilic than neutral species because

A

they want to share electrons to relieve the negative charge.

41
Q

pKa of alcohols

A

16

42
Q

pKa of phenols

A

10

43
Q

pKa of carboxylic acids

A

5

44
Q

Polar Aprotic solvents used in SN2 reactions where strongest base = strongest Nu

A

DMSO
DMF
DMA
HMPA
acetone
THF

If the solvent is polar aprotic then it is SN2 because we can dissolve the SM, stabilizes the charge better, and stabilizes the TS.

45
Q

Polar Protic solvents used in SN1, E2, and E1 reactions where the strongest base = weakest Nu

A

H2O
EtOH, MeOH
NH3
AcOH

46
Q

How are nucleophiles affected by sterics?

A

More sterics = bad nucleophile
Less sterics = good nucleophile

47
Q

Predict the product and state whether this is SN1, SN2, E1, or E2

A

SN2

48
Q

Predict the product and state whether this is SN1, SN2, E1, or E2

A

SN2

49
Q

Predict the product and state whether this is SN1, SN2, E1, or E2

A

SN2

50
Q

Predict the product and state whether this is SN1, SN2, E1, or E2

A

SN2

51
Q

How many steps are in SN1?

A

2

52
Q

Name the reaction of this general scheme

A

SN1

53
Q

Show the mechanism for this SN1 reaction

A
54
Q

What is the rate trend of the L.G. class in SN1 reactions?

A
55
Q

What is the pKa L.G. trend for SN1?

A
56
Q

Predict the product of this SN1 reaction

A
57
Q

Predict the product of this SN1 reaction

A
58
Q

Predict the product of this SN1 reaction

A
59
Q

Predict the product of this SN1 reaction

A
60
Q

Predict the product of this SN2 reaction

A
61
Q

Predict the product of this SN1 reaction

A
62
Q

Predict the product of this SN2 reaction

A
63
Q

Predict the product of this SN1 reaction

A
64
Q

What is Zaitsev’s rule and when is it used?

A

The major product is the more substituted/stable product. Used in E2 reactions

65
Q

What are the exceptions to Zaitsev’s Rule?

A

All follow Hoffman’s which is anti=Zaitsev
Conjugated Alkenes
Big Bulky Bases
Fluorine L.G.

66
Q

Predict the product of the following E2 reaction

A
67
Q

Predict the product of the following E2 reaction

A
68
Q

Predict the product of the following E2 reaction

A
69
Q

Predict the product of the following E2 reaction

A
70
Q

Predict the product of the following E2 reaction

A
71
Q

Predict the product of the following E2 reaction

A
72
Q

Predict the product of the following E2 reaction

A
73
Q

What are the rates of leaving groups I, Br, Cl, F in E2 reactions?

A
74
Q

Strong charged bases such as NaOH, KOH, NaOCH3 and KOEt can do both SN2 and E2 rxns. How do we determine which way the rxn will go?

A

pKa values and the class of L.G.
When pKa > 11 then E2 because basic
When pKa < 11 then SN2 because nucleophilic

75
Q

Write the mechanism for the following E1 rxn

A
76
Q

Does heat favor E1 or SN1? Do warm conditions favor E1 or SN1?

A

Heat favors E1 and warm conditions favor SN1

77
Q

How many steps are there in E1 rxns?

A

2

78
Q

What reaction is described below?
Properties:
1. Rate depends on formation of carbocation. 3 > 2 >(1 does not form)
2. The alkene formed is on the most substituted and thermodynamically stable carbon
3. Mechanism has rearrangments
4. Rate of L.G. = I > Br > Cl > (F does not form) and H2O (dehydration)

A

E1

79
Q

Write the mechanism for the following E1 reaction

A
80
Q

Write the mechanism for the following E1 reaction

A
81
Q

Predict the product of the following rxn

A
82
Q

Predict the product of the following rxn

A
83
Q

Predict the product of the following rxn

A
84
Q

Predict the product of the following rxn

A
85
Q

Complete this radical halogenation mechanism

A
86
Q

Complete this Gilman reaction

A
87
Q

Why would concentrated HBr be an inappropriate catalyst for the dehydration of alcohols?

A

The conjugate base Br is a good nucleophile and it would attack the carbocation to form an alkyl bromide.

88
Q

What would be the first step in the dehydration of cyclohexanol in sulfuric acid?

A

protonation of the alcohol

89
Q

What time of reaction is a one step process with inversion of configuration?

A

SN2

Organic Chemistry I (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions