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 terminus to an organosilicon group.
Contents
- Organic synthesis
- Organic reactions
- SaegusaIto oxidation
- Ring contraction
- Ketene silyl acetals
- References
Silyl enol ethers are important intermediates in organic synthesis.
Organic synthesis
Organic reactions
Silyl enol ethers react as nucleophiles in:
Saegusa–Ito oxidation
In the Saegusa–Ito oxidation certain silyl enol ethers are oxidized to enones with palladium(II) acetate. In the original publication equal amounts of palladium and 1,4-benzoquinone are used to achieve the reaction with the benzoquinone acting as a co-oxidant. The intermediate is an oxo-allylpalladium complex.
In one application, a dienone is synthesized in two steps from a cyclohexanone:
Ring contraction
Cyclic silyl enol ethers have been demonstrated to be viable substrates for regiocontrolled one-carbon ring contractions. These reactions employ electron-deficient sulfonyl azides, which undergo chemoselective, uncatalyzed [3+2] cycloaddition to the silyl enol ether, followed by loss of dinitrogen, and alkyl migration to give ring-contracted products in good yield. These reactions may be directed by substrate stereochemistry, giving rise to stereoselective ring-contracted product formation.
Ketene silyl acetals
Ketene silyl acetals are related compounds formally derived from ketenes and acetals with general structure R-C=C(OSiR3)(OR').