A-Silylcarbonyl compounds

The 1,3-silyl migrations from O to C in lithiated silyl enol ethers 205 afforded a-silylcarbonyl compounds 206 after hydrolysis (equation 134)326 -330. 

On the action of Grignard compounds, a, 3-epoxysilanes undergo rearrangement to a-silylcarbonyl compounds, eo f/tra-lS-hydroxysilanes being formed in a very stereoselective reaction. ... 

Another, final, example of C-C(sp ) coupling is the so-called Peterson olefination [89, 90] (Scheme 1.42). Lithium T -silylethylalkoxides, accessible either by reaction of a-silylalkyllithium compounds with carbonyl compounds or of organoiithium compounds with a-silylcarbonyl compounds, readily extrude hthium silox-ides to leave C=C double-bond products. a-SilylaUcyllithium compounds can therefore be regarded as alkylidenating agents for carbonyls. 

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