Ethyl methoxymethyl ketone

Anion Trap. Besides formation of silyl enol ethers, TMSCl has also been applied to trap other oxide anions to form the desired trimethylsilyl derivatives. For example, reaction of ethyl 4-phenylbutanoate with l,l-dichloroethylUthium, which was generated from 1,1-dichloroethane and LDA, produced exclusively the mixed acetal as expected in 86% yield in the presence of TMSCl (eq 44). Without TMSCl, the reaction gave the corresponding ketone as the final product. However, the yield is rather low and the ketone was obtained in only 16% (eq 45). When the same reaction run with methoxymethyl 4-phenylhutanoate, it... 

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