nucleophilic addition - chapter 6 Flashcards

1
Q

when a nucleophile attacks the carbonyl group which orbital do the electrons enter

A

the pi* orbital, which breaks the carbonyl bond

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

how does the electron pair entering the pi* orbital cause the pi bond to break

A

the electrons break the pi system, destabilising the bond

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

when the carbonyl bond breaks, where are the electrons transferred

A

onto the oxygen which forms a negative charge

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

why are aldehydes more reactive than ketones

A
  1. steric hindrance - ketones have two R groups thus having a larger steric hindrance than aldehydes
  2. aldehydes have one less R group attached to the carbonyl bond - there is less + inductive effect therefore the delta positive charge on the
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the most important factor to consider when deciding how acidic a molecule is

A

its resonance structures

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

why are organometallic reagents powerful nucleophiles

A

due to the great difference in electronegativities between the carbon group and the metal, the bond is very polar

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

what effect does protonating the carbonyl group have on a molecule

A

it makes the carbon more electrophilic
it increases the rate of the reaction
this makes it more attractive for the nucleophile

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

what does an acid catalyst contribute to a nucleophilic reaction

A

it protonates the carbonyl group, making the carbonyl more electrophilic

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

what does having a basic catalyst contribute to a nucleophilic reaction

A

it de-protonates the nucleophile, making the nucleophile more nucleophilic

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

why is sodium bisulphate added to aldehydes and ketones

A

for purification

sulfur atom has lone pair

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