Alpha Carbon Chemistry: Enols & Enolates cont Flashcards
When performing a claisen condensation reaction the starting ester must have _________
Have 2 alpha protons
If another type of ester base was used instead of the group on the ester then a ____________ reaction will occurs & convert the present group on the ester to a different group
Transesterification
Cross Claisen condensations
Are claisen condensation reactions that occur between two different partners
What are the two criteria need for a claisen condensation reaction to occur?
- If one ester has no alpha protons & can’t form an enolate
- A direct claisen condensation can be performed in which LDA is used as a base to irreversibly form an ester enolate, which is then treated with a different ester
Dieckmann cylcization
When claisen condensation undergo an intramolecular reaction where the product is a cyclic beta keto ester
Intramolecular claisen condensation show a preference for formation of a ____ or ___ member ring due to ring strain
5 or 6
The aloha position of a ketone can be alkylated by what two steps?
- Formation of an enolate
- Treating the enolate with an alkyl halide
For alkylation reaction ______ is the base used
LDA
The malonic ester synthesis
Is a technique that enables the transformation of halide into carboxylic acid with an introduction of two new carbon atoms
The reagent used in a malonic ester synthesis is ____________
Diethyl malonate
The 1st step in malonic ester synthesis is the ___________ of diethyl malonate
Deprotonation
After the 1st step in a malonic ester synthesis what happens?
Then the enolate is treated with an alkyl halide resulting in an alkylation step
Treatment with ________ results in the hydrolysis of both ester groups
aqueous acid
If hydrolysis is performed at high temp then decarboxylation occurs to produce a ____________ where the enol then undergo tautomerization
monosubstituted acid & carbon dioxide
Acetoacetic ester synthesis
Is a technique used to convert an alkyl halide into a methyl ketone introducing 3 new carbons
What reagent is used for an acetoacetic ester synthesis
The reagent used is ethyl acetoacetate
An alpha beta-unsaturated aldehyde or ketone has _____ electrophilic positions one at the beta position & other is the carbon of the carbonyl group
Two
Both electrophilic positions can be attack by a __________
Nucleophile
Grignard reagent tends to attack the ______ rather than the beta position
Carboynl group
Micheal reaction
When the starting diketone is deprotonated to form a doubly stabilized enolate ion which then serves as a nucleophile in a 1,4-conjugate addition
The doubly stabilize anolate is called a _______ & the alpha beta- unsaturated aldehyde is called a __________
Micheal donor, micheal acceptor
Only doubly stabilize enolates can be a ___________ not regular enolate
Micheal donor
A ketone can be converted into an _______ when treated with a secondary anime
Enamine
An enamine can function as a _________ to undergo a Michael reaction
Micheal donor
When treated with aquoues acid both NR2 & enolate are converted into _______
carbonyl groups
Stork enamine synthesis
Convers a ketone into an enamine to undergo a Micheal reaction & hydrolysis
Robinson annulation
Two step reaction where a Michael reaction is followed by an intramolecular aldol condensation reaction to make a polycyclic compound
The aldol addition, Claisen condensation, & stork enamine produce ___________
Difunctional compounds
Aldol addition & Claisen produce ________ & stork produce 1,5 difunctional compounds
1,3 difunctionals
In a micheal reaction the enolate can be treated with ______ to give the product
water
In a Micheal rection the enolate can also be treated with an _______ which results in alkylation in the alpha position
an alkyl halide
When adding the alkyl group they cant be the ______
Same
