Enolates trimethyl silyl chloride

Enol silyl ethers of acylsilanes. On treatment with butyllithium and trimethyl-silyl chloride, these compounds undergo enol silylation, tellurium-lithium exchange, and O — C silyl migration. The lithium enolates are further silylated. 

Sometimes a Lewis acid such as zinc iodide is added in catalytic amounts. Side reactions may sometimes occur if acyl cyanides carry hydrogen atoms in the a-position and are, therefore, enolizable. In those examples trimethylsilyl chloride, which is formed during the reaction, may react to give trimethyl-silylated enol ethers (8). This methodology can be applied successfully to the synthesis of such com-... 

A sample of racemic 2-methylcyclohexanone-1- 3 was prepared by methylation of the lithium cyclohexanolate-l-13 , with methyl iodide (VI ) The enolate was prepared from the cyclohexanone-1-13c by way of the trimethyl silyl derivative following the pro-" cedure of House and coworkers (12). A sample of trans-D,l-2-methylcyclohexanol-l -13C was then obtained by reduction of the ketone with lithium aluminum hydride in the presence of aluminum chloride as prescribed by Eliel and coworkers (13). 

Monoprotected P-keto-aldehydes may be prepared by the a-dialkoxymethyl-ation of pre-formed enolates or enamines with trimethyl orthoformate and boron trifluoride diethyl etherate. Regiospecificity is maintained when the enolate is released from the silyl enol ether with methyl-lithium. P-Keto-acetals or P-diketones may also be formed by acylation of enol ethers with acid chlorides. High yields depended on the use of activated acid chlorides, such as a-halo- or a-cyano-acetyl chlorides. Enaminosilanes are acylated by a wide range of acid chlorides in the presence of potassium fluoride and a crown ether, giving very high yields of the enaminone [equation (46)]. Under the reaction conditions,... 

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