Acyl tetracarbonylferrates

Among other reactions, the bis-metallated species (151) derived from nitroalkanes condense with dialkyl carbonates to give comp>ounds (152), in 60—80% yield, which can serve as precursors of both a-amino-acids and a-hydroxyamino-esters as well as a-keto-esters. Oxazolin-5-ones (153) can be alkylated at the 4-position by alkyl halides in hot DMF containing HMPA and ethyldi-isopropylamine. Yields are good (60—90%) for allylic, benzylic, and propargylic halides but otherwise poor (e.g. 32% with EtI) under these conditions acid hydrolysis of the products affords substituted a-amino-acids. Mesoionic l,3-oxazol-5-ones (154), obtained from imidoyl chlorides and acyl-tetracarbonylferrates, react with alcohols to give N-acyl-a-amino-acid esters. ... 

Azolides are also capable to acylate anionic metal carbonyl compounds. For instance, disodium tetracarbonylferrate as well as the corresponding ruthenium and osmium compounds can be formylated with formylimidazole in the presence of boric acid methyl ester ... 

Unsymmetrical ketones of the type RfCOR [Rf = n-CsF , n-C Fi5, or CeFs R = hydrocarbon system which may contain a functional group (ester, nitrile, or chlorine)] can be synthesized in good yield by (i) successive treatment of disoidium tetracarbonylferrate(ii) in THF with an acid chloride RfCOCI and then an alkylating agent [e.g. Na2Fe(CO)4 -I- n-CyFis CCCl + PhCHsBr — -n-C7Fis CO CH2Ph (59%)] or (ii) successive treatment of the ferrate with an alkyl or acyl halide or... 

The utility of sodium tetracarbonylferrate(—u) in the selective stereospecific synthesis of unsymmetrical aliphatic ketones has been outlined various conditions, to accommodate difierent substrates, are delineated (Scheme 71). The intermediates in such reactions, alkyl (26) and acyl (27) tetracarbonylferrate salts, have been isolated the i.r. spectra are consistent with the shown C3 symmetry, the bulky alkyl or acyl group being at the apical position of a trigonal bipyramid. 

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