L20 - Alkenes As Electrophiles Flashcards
What are aromatics like?
Weak nucleophiles
- undergo electrophilic substitution RXN
(Can aslo be electrophiles SnAr)
What are isolated double bonds like?
Nucleophilic
- alkenes undergo electrophilic addition RXN
What are carbonyls like?
Electrophiic
- at the carbonyl C
What are conjugated carbonyls called (not cyclic)?
Alpha-beta unsaturated carbonyl
What do enones have?
Allylilc carbocations
What are allylic carbocations?
Carbocations that can move electron density around
- also moves the positive charge of the carbocation
What are the 2 types of reactions that a-B unsaturated carbonyls can go through?
- direct addition // 1,2 addition
- conjugate addition // 1,4 addition // Michael addition
What happens in direct addition // 1,2 addition?
- Nu- attacks carbonyl C
- forms tetrahedral intermediate
X = LG
- kicks X out, reforms db
X /= LG
- forms hydroxyl group
What happens in conjugate addition // 1,4 addition // Michael addition?
- Nu- attacks B C
- moves db and forms O-
- O- attacks back
- db protenated by HA through C
What is most likely to readily react as 1,2 addition? And 1,4 addition?
1,2
- acyl chloride
- aldehyde
- ketone
- ester
- amide
1,4
What is the important part of glutathione?
R-SH
Why is it toxic to have electrophiles in the body?
Can react with nucleophiles in the body
(DNA, can alter it)
What does glutathione do in the body?
Modifies electrophiles in the body
- preventing alteration of DNA
