Chapter 8 - Substitution and Elimination Flashcards Preview

DAT - Organic Chemistry > Chapter 8 - Substitution and Elimination > Flashcards

Flashcards in Chapter 8 - Substitution and Elimination Deck (10)
Loading flashcards...
1
Q

Why is I a better leaving group in comparison to Cl, Br, and F?

A

Large size

better leaving group in order

F < Cl < Br < I

2
Q

Which reaction will give a racemic mixture

a) SN1
b) SN2
c) E1
d) E2

A

A

3
Q

Differentiate between SN1 and SN2 reactions in regards to:

  • weak or strong nucleophiles
  • stereochemistry of the product
  • whether rearrangement can occur
A

SN1 - weak nucleophile, no stereochemistry involved, gives racemic products, rearrangement possible

SN2 - strong nucleophile, inversion of stereochemistry, no carbocation formation

4
Q

When trying to determine if a reaction is SN1 or SN2, how can you differentiate between a strong or weak nucleophile?

A

strong nucleophile = resonance stabilized or has a negative charge

weak nucleophile = lone pairs

5
Q

What is the rate for SN1 and SN2 reactions?

A

SN1: rate = k [electrophile]

SN2: rate = k [electrophile][nucleophile]

6
Q

Halogens prefer to do ____ reactions

A

SN1

7
Q

T/F? Rearrangements happen in both E1 and E2 reactions

A

FALSE - they can only happen in E1

8
Q

E1 and E2 reactions will usually give the Zaitsev’s product. In what condition will either reaction yield the anti-Zaitsev?

A

If a bulk base is used

9
Q

In E2 reactions, the H being plucked off by the strong base must be in what type of formation?

A

anti-coplanar to the leaving group

10
Q

How do you determine if the nucleophile or base is acting as a nucleophile or a base?

What is the exception to this rule?

A

If it’s bigger than CH3CH2OH = elimination (acts as a base)

smaller than CH3CH2OH = substitution (acts as a nucleophile)

acetate is bigger than ethanol, but it prefers to do substitution