Ethyl formate reaction with Grignard reagents

In a related reaction, treatment of the lithinm salt of diethyl (l-phenylsulfonyl)ethylphosphonate with triflnoroacetic anhydride affords triflnoroacetylated phosphonate, which, without isolation, reacts with Grignard reagents in THF at reflux to give trifluoromethylated vinylsulfones in 42-55% yields, with the formation of ( )-isomer exclusively or predominantly. Treatment of the lithium salt of diethyl 1-fluoro-l-(ethoxycarbonyl)methylphosphonate with trimethylsilyl trifluoroacetate leads to the enolate of ethyl (trifluoroacetyl)fluoroacetate, which can further undergo protonation, alkylation, or allylation. °5... 

Next to the formation of Grignard reagents, the most important application of this reaction is the conversion of alkyl and aryl halides to organolithium compounds, but it has also been carried out with many other metals, (e.g., Na, Be, Zn, Hg, As, Sb, and Sn). With sodium, the Wurtz reaction (10-93) is an important side reaction. In some cases, where the reaction between a halide and a metal is too slow, an alloy of the metal with potassium or sodium can be used instead. The most important example is the preparation of tetraethyl lead from ethyl bromide and a Pb—Na alloy. 

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