Brainscape's Knowledge GenomeTM

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


See full index

Organic Chemistry > Elimination Reaction > Flashcards

Elimination Reaction Flashcards

1
Q

In an ___________ reaction a proton from the Beta position is removed with the leaving group to form a double bond

A

Elimination

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

The product of an elimination reaction will always have a ________ & be a _________

A

Double bond, alkene

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

Alkenes are named the same way as alkanes but end in _______

A

“ene”

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

When naming alkenes have to make sure what?

A

That the longest parent chain includes the double bond & that the double bond has the lowest possible number

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

Alkenes are also classified by their _______________

A

Degree of substitution

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

Degree of Substitution

A

Refers to the number of akyl groups connected to a double bond (Monosubstituted - tetrasubstituted)

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

Bredt’s Rule

A

States that its not possible for a bridgehead carbon of a bicyclic compound to have a double bond if it involves a trans configuration in a small ring

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

Bridge bicyclic compounds can only have a double bond at a bridgehead position if one of the rings has at least ___________

A

Eight Carbons

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

Cis & Trans is used to compare ______ similar group on a carbon where E & Z is used when comparing _______

A

One, two or more

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

Cis alkenes are __________ than trans alkenes because it experience steric strain from being on the same plane

A

Less stable

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

Alkenes are more stable when they are _____________

A

High substituted like tetrasubstituted alkenes

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

____________ are products of an elimination reaction

A

Alkenes

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

What are the two core steps in an elimination reaction ?

A
  1. Proton Transfer
  2. Loss of leaving group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In a ___________ a base takes a proton & the leaving group leaves at the same time

A

Concerted Reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In a ______________ 1st the leaving group leaves & then the base takes a proton

A

Stepwise reaction

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

The ______ mechanism is the concerted reaction

A

E2

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

How is an E2 reaction similar to SN2 reactions?

A

Its biomolecular where the rate law is R =k [substrate][base] (rate depends on both the substrate & base)

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

__________ substrates favors E2 reactions because with steric hindrance it prevents a reagent from functioning as a nucleophile (like in SN2) at a fast rate but the reagent can still function as a base (E2) without encountering much steric hindrance

A

Tertiary Substrates

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

The Ea in an E2 reaction is smallest with ________ substrate & largest with primary substrate because its least favored

A

Tertiary

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

Regiochemistry

A

When the beta (β) position aren’t identical (one may be on a methyl the other may be on an ethyl) which will result in multiple products being formed where the more substituted one is the major one

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

The more susbtituted product (the major product) is called what?

A

Zaitsev product

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

Hofman product

A

The less substitutted alkene (minor product)

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

When stereically hindered bases are used in an E2 reaction the ___________ is the major product

A

Hofman product (A base can be used to control the product of an E2 reaction)

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

When there are two stereoisomer (cis or trans) as the product in an E2 reaction then the _______ will be the major product

A

Trans

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

Coplanar

A

When the atoms are on the same plane

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

Anti-coplanar (anti-periplanar)

A

Forms a staggered newman projection

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

Syn-coplanar (Syn-periplanar)

A

Forms an eclipsed newman projection

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

E2 reaction has to be in ____________ conformation to react

A

Anti-periplanar (Anti-coplanar) (Dihedral angle of 180°)

29
Q

In a stereoselective E2 reaction

A

The substrate can produce two stereoisomeric products (Either cis or trans)

30
Q

In a stereospecific E2 reaction

A

The substrate is stereoisomeric & the stereochemical product is dependent on which stereoisomeric is used

31
Q

An E2 reaction occurs by a ____________ conformation

A

Anti-periplanar

32
Q

For an E2 reaction to occur with a cyclohexane chair conformation the leaving group must be on the _________ position to be anti-periplanar & react

A

Axial position

33
Q

E2 reaction can only happen with cylcohexanes (or any rings) when the leaving group & beta hydrogens are on ___________

A

Opposite planes (If the LG is on a wedge then the Beta hydrogens has to be on a dash to form the anti-periplanar to react)

34
Q

The _______ mechanism is the stepwise reaction

35
Q

What is the rate law of an E1 reaction?

A

R = k[substrate] (unimolecular) (The rate determing step is the loss of LG)

36
Q

__________ halides favor the E1 mechanism & primary are least favored because the 1st step in E1 is the loss of LG which forms a carbocation & primary carbocation are least stable)

A

Tertiary halides

37
Q

In an E1 reaction if an alochol is the leaving group then a ______________ is needed to protonate it

A

Strong acid

38
Q

In an E1 reaction the regiochemistry can’t be controlled by a base & the ______________ is usually produced

A

Zaitsev product

39
Q

E1 don’t need a anti-periplanar conformation to react & favors the _________ product when stereoisomers are the products

40
Q

What are the two core steps of an E1 reaction?

A
  1. Loss fo LG
  2. Proton transfer
41
Q

What are the only 2 additional steps an E1 reaction can have?

A
  1. Proton transfer before the 1st step (loss of LG)
  2. Carbocation rearrangment in between the two core steps
42
Q

A proton transfer is needed at the beginning of an E1 reaction if an _________ is the leaving group & is needed to be protonated

43
Q

A carbocation rearrangement is needed in the middle of an E1 reaction if the carbocation can be ____________

A

More stable

44
Q

An E2 reaction has ________ additional steps

A

Zero its only a concerted reaction where the proton transfer & loss of Lg occur aqt the same time

45
Q

Why doesn’t E2 reaction have any additional steps?

A

It can’t form a carbocation & it uses strong bases & an OH can’t be protonated with a strong base

46
Q

___________ & ___________ reactions are always in competiton where sometimes one mechanims donminates & forms one product & other times both dominate & form multiple products

A

Substitution & Elimination reaction

47
Q

How do you determine which product is major & minor?

A
  1. Determine the function of the reagent
  2. Analyze the substrate & determine the expected mechanisms
  3. Consider any relevant regiochemical & stereochemcial requirements
48
Q

A substitution reaction occurs when the reagent acts as a ___________ & an elimination reaction occurs when the reagent acts as a _________

A

Nucleophile, Base

49
Q

Nucleophilicity

A

A kinetic phemomeon & refers to the rate of the reaction (refers to the rate at which a nucleophile attack an electorphile)

50
Q

Basicity

A

A thermodynamic phenomeon & refers to the position of equilibrium

51
Q

Factors that contribute to nucleophilicity

A
  1. Charge on an atom
  2. Polaraziability (More important than charge)
52
Q

Polarziabaility is directly portportional to the _________

A

Atomic mass

53
Q

In a proton equilbium it will favor the _________

A

The weaker base

54
Q

Reagents that are only strong nucleophiles indicates what type of reaction?

A

Substitution reaction

55
Q

What are the reagents that are only strong nucleophiles?

A
  1. Cl- 5. RS-
  2. Br- 6. H2S
  3. I- 7. RSH
  4. HS-
56
Q

Reagents that act only as strong bases indicate what type of reaction?

A

Elimination reaction

57
Q

What are the reagents that function only as strong bases?

A
  1. H-
  2. DBN
  3. DBU
58
Q

Reagents that function as both strong nucleophile & strong bases indicates what type of reaction?

59
Q

What are the reagents that are both strong bases & nucleophiles?

A
  1. HO-
  2. MeO-
  3. EtO
  4. RO-
60
Q

Reagents that are both weak nucleophile & bases indicate what type of reaction?

61
Q

What reagents function as both weak nucleophile & base?

A
  1. H2O
  2. MeOH
  3. EtOH
  4. ROH
62
Q

Protic solvents favor what type of reactions?

63
Q

Aprotic solvents favor what type of reaction?

64
Q

When a ______________ base is present (ex. t-ButOK) then the major product is the hofman product

A

Sterically Hindered (Bulky bases)

65
Q

______________ are a result of a sterically base being used

A

Less substituted

66
Q

__________________ refers to beta positions being identical or not (where if they are identical then one product will be formed & if they are non-identical then two or more products formed)

A

Regiochemistry

67
Q

When regiochemistry is not a factor (only have one beta position) then if there is two hydrogens on the beta position then _______________ comes into play where the trans conformation is the mjaor product

A

Stereoselectivity

68
Q

When regiochemistry & stereoselective isn’t a factor because only one beta position & there is only one hydrogen present then _______________ comes into play where have to make a newman projection so that the leaving group & beta hydrogen are anti-perilinear & then have to draw the newman projection that make them anti-perilinear

A

Stererospecific

Organic Chemistry (47 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions