L12 - Nucleophilic Substitution (SN1/SN2/E1/E2) Flashcards
1
Q
What is a nucleophile?
A
Region of high e- density
Lp/negative charge
2
Q
What is an electrophile?
A
Region of low e- density
3
Q
What is a good leaving group able to do?
A
Stabalise a negative charge
4
Q
What are the steps in SN2?
A
- Nu- attacks 180
- transition state with 5 specied
- LG leaves
- inversion of chemistry
5
Q
What are factors for SN2?
A
- v good Nu
- primary + secondary substrates
6
Q
What are the steps for SN1?
A
- LG leaves
- tertiary carbocation intermediate
- forms racemic mixture
7
Q
What is the rate determining step in SN1?
A
The LG leaving
- slowest steps
8
Q
How does SN1 form a racemic mixture?
A
Because the Nu- can attack from either side of the p-orbital
9
Q
What are factors for SN1?
A
- v good leaving group
- weak Nu
- large Nu
- stabilised carbocation
10
Q
What are the steps in E2?
A
- base attacks proton
- e- move to form db
- LG leaves
11
Q
What are the steps in E1?
A
- LG leaves
- base attacks proton
- e- moves to form db
