Silyl anions alkoxy-substituted

Recently Yoshida et al. have employed silyl-stabilized a-alkoxy organolithium reagents for the synthesis of a variety of carbonyl compounds. Methoxy(trimethylsilyl)methane and methoxybis(trimethyl-silyl)methane, when deprotonated with Bu Li and Bu"Li respectively, give anions which can be alkylated with a variety of electrophiles. Electrolysis of a solution of the alkylated product in methanol yields, by virtue of the reduced oxidation potential of ethers a-substituted with silicon, either the dimethyl acetal or in the latter case the orthoester. The mildness of the electrolytic process recommends the method for the preparation of a variety of carbonyl compounds. 

The above example illustrates the influence of the fS-stabdizing effect of silicon, which is well known for reactions involving carbocationic intermediates [70]. In contrast, less is known about the P-destabiUzing effect of siHcon on aUyic anions. In the present example, an allylic alkoxy anion is generated with methoxide from the silyl-substituted enol acetates 214 and 217 (Scheme 3.46) [71]. 

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