Silicon-oxygen single bond

The 1,2-migration of a silicon moiety to the oxygen anion of a carbon-oxygen single bond produced by nucleophilic addition to a carbonyl group (Brook... 

Definition Astraight-chain compd. consistg. of silicon atoms single-bonded to oxygen and arranged so that each silicon atom is linked with four oxygen atoms Properties Nonionic... 

Figure 6,4 Ternary plot of singly bonded oxygen 0 , silicon Si and bridging oxygen in each kind of polyanion. Shaded areas compositional ranges 6.31 and 6.33. Reprinted from Ottonello (1983), with kind permission of Theophrastus Publishing and Proprietary Co.

Second only to lithium enolates in usefulness are silyl enol ethers. Silicon is less electropositive than lithium, and silyl enol ethers are more stable, but less reactive, than lithium enolates. They are made by treating an enolate with a silicon electrophile. Silicon electrophiles invariably react with enolates at the oxygen atom firstly because they are hard (see p. 237) and secondly because of the very strong Si-O single bond. The most common silicon electrophile is trimethylsilyl chloride (Me3SiQ), an intermediate made industrially in bulk and used to make the NMR standard tetramethyl silane (Me4Si). 

Silicon most often forms single bonds and, as a result, when it bonds to oxygen it bonds to four different atoms. This type of bonding gives rise to the numerous chain and sheet structures that were described earlier. However, the bonds need not all be to oxygen atoms, and many compounds are known in which alkyl groups are bonded to the silicon. The reaction... 

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