Silyl- and germylmercurials in organic synthesis. A new route to O-silylated and O-germylated enolates

The exchange reaction of α-mercurated ketones with bis(triethylsilyl)- (I) and bis(triethylgermyl)mercury (II) leads to the formation of the corresponding triethylsilyl and triethylgermyl enol ethers. O-Silylated and O-germylated enolates derived from ketones and aldehydes can be also prepared by treating mercurials I and II with appropriate α-bromo-carbonyl compounds. This new pathway also represents the best available method for preparing bromo-containing triethylsilyl and triethylgermyl enol ethers. NMR and IR spectral characteristic useful in the identification and characterization of these and related compounds are summarized.