How do you make silyl enol ether?

Synthesis. Silyl enol ethers are generally prepared by reacting an enolizable carbonyl compound with a silyl electrophile and a base, or just reacting an enolate with a silyl electrophile.

What is an Enolate in organic chemistry?

Enolates are organic anions derived from the deprotonation of carbonyl compounds. Rarely isolated, they are widely used as reagents in the synthesis of organic compounds.

What is an enol intermediate?

Enols, or more formally, alkenols, are a type of reactive structure or intermediate in organic chemistry that is represented as an alkene (olefin) with a hydroxyl group attached to one end of the alkene double bond. The keto and enol forms are said to be tautomers of each other.

What is alpha hydroxy ketone?

α-Hydroxy ketone (alpha-hydroxy ketone; acyloin): A molecule containing adjacent ketone and alcohol groups. General α-hydroxy ketone structure. Acyclic D-fructose has two α-hydroxy ketone moieties, shown in red.

What is the synthetic purpose of forming a silyl ether?

Formation of Silyl Ethers Silyl ethers are inert to many reagents that react with alcohols, so they serve as protecting groups in organic synthesis.

Why is Enolates a strong nucleophiles?

“the conjugate base is always a better nucleophile”. I said enols were good nucleophiles. But their conjugate bases – enolates – are even better. Enolates have two resonance forms – we can put the negative charge on the oxygen or the carbon.

How is an enolate formed?

Enolates, formed by the abstraction of the α hydrogen atom by a strong base, are nucleophiles. Lithium diisopropylamide (LDA) or sodium hydride are required as bases. The site of proton abstraction is related to the acidity of the two possible α hydrogen atoms, which is in the order primary > secondary > tertiary.

What is the general structure of silyl enol ether?

The general structure of a silyl enol ether. Silyl enol ethers in organic chemistry are a class of organic compounds that share a common functional group composed of an enolate bonded through its oxygen end to an organosilicon group. Silyl enol ethers are important intermediates in organic synthesis.

How do you make trimethylsilyl enol ethers?

Trimethylsilyl enol ethers can be prepared from ketones in presence of a strong base and trimethylsilyl chloride or a weak base and trimethylsilyl triflate. Alternatively, enolate salts react with silyl electrophiles. A rather exotic way to generate silyl enol ethers is via the Brook rearrangement of appropriate substrates.

Is dicobalt octacarbonyl a good catalyst for the formation of enol ether?

Sakurai177 has found that dicobalt octacarbonyl is an excellent catalyst for the reaction (equation 67) and that the side reactions occurring through the use of the catalysts mentioned above ( e.g. silyl ether formation) may be avoided. The silyl enol ether obtained arises from the thermodynamically stable enol.

How do silyl enol ethers react with carbocations?

Silyl enol ethers react with carbocations to form a carbon–carbon bond upon the release of the trimethyl silyl group.481 Verma et al. 482 prepared ester end-functionalized poly (vinyl ether)s by end-quenching the HI/ZnI 2 -initiated system with dimethyl (trimethylsilyl)methyl ketene acetal in the presence of tetrabutylammonium benzoate.