摘要：

It was found that silyl enol ethers, prepared from various carbonyl compounds, react with aldehydes and ketones in the presence of titanium tetrachloride under mild conditions to give cross-aldol addition products in good yields. A monomethylol product, 4-hydroxy-3-phenyl-2-butanone, was prepared in good yield from 1-phenyl-2-trimethylsilyloxy-1-propene and trioxane. Further, regiospecific addition of carbonyl compounds was observed with silyl enol ethers, derived from unsymmetrical ketones, such as phenylacetone or 2-methylcyclohexanone.

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