423 notes1 Flashcards
Ester plus 1. NaOEt 2. H3O+
adds ketone
Can claisens react between different esters?
Yes
What is required for claisen?
Ester needs 2 alpha protons
Requirement for crossed claisen (2 different esters(
- One of the pair has no alpha protons
- Use LDA to perform enolate
What reacts in intramolecular claisen?
electrons on inner side of ketone and partial positive carbon. Kicks off OEt, creates cyclic structure
LDA with keton
Adds - charge at end of carbon
RX with ketone with - charge at end
Adds R at - charge carbon
Enolate with kinetic base
opposite of r
Enolate with thermodynamic base
same side as r
RX –> RCH2COOH
diethylmalonate. Can deprotonate with OEt, add a halide with RX, cleave leaving R with H3O+. Can be done 2x.
Alkyl halide –> ketone
uses acetoacetate. Deprotonates central H, leaving -, RX adds R. H3O+ cleaves, leaving R. Can be done 2x.
DB next to carbonyl
Alpha beta unsaturated carbonyl
Do nucleophiles attack carbonyl or db?
Depends on their preference
Stronger nucleophiles (Organolithiums, grignards) attack
Carbonyl
Michael reaction
1, 4 reaction
Michael donor
Extra LP
Michael acceptor
DB
- LDA 2. MVK 3. H3O+ with dienolate
works well, adds alkyl with carbonyl at far end
- LDA 2. MVK 3. H3O+ with enolate
works poorly
enolate with 1. NR2H 2. H+ (-H2O
Creates enamine (nitrogen version of enolate, 1,4 rxn)
Dienolate with sticky outy thing plus michael addition
Adds to mark, NaOH and heat can fuse structure and remove carbonyl
Make a 1, 3 dicarbonyl compound
Use claisen (1. NaOET 2. H3O+)
- Make 1, 5 dicarbonyl
Use michael (1. R2NH 2. Enolate 3. H2O)
Add R groups to ketones
Start with ethyl acetoacetate. 1. 2X NaOEt 2. (RX 2x) 3. H3O+
Carbonyl with DB adjacent reacted with R2CuLi, then H2O
Adds R at meta
Carbonyl with DB adjacent with R2CuLi, then RX
R at ortho and meta
