Formamides with organometallic

The structural investigation of organometallic intermediates benefits the understanding of reaction mechanism and further reaction chemistry (Scheme 2.6). The reactive intermediate 2-6 features Zr-C(sp ) bond, which was proved to be useful for further synthetic application. 2-6 could react with several unsaturated compounds or electrophiles such as isocyanide, formamide, acid chloride, and aldehyde, alfording a series of A -heterocycles upon hydrolysis (Scheme 2.7). 

Like formamides, homologous carboxamides may also be used for the acylation of organometallics unless the latter are sterically crowded. 2,6-Dichlorophenyllithium and other 2,6-disubstituted aryllithiums can only combine with dimethylformamide. If tetramethyloxalamide is treated with one equivalent of organolithium prior to hydrolysis, a 2-oxocaui>oxamide is obtained, with two equivalents symmetrical v/c-diketones. ... 

In many cases, organometallic intermediates formed by this method are poorly stable. They react with classical organic solvents used in electrochemistry (dimethyl-formamide, acetonitrile, N-methylpyrrolidinone, etc.). However, they can also react more rapidly with some electrophiles present in the medium, leading to interesting C-C bond-forming reactions. 

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