Reaction with tetracarbonylferrate

Anhydrides, both aliphatic and aromatic, as well as mixed anhydrides of carboxylic and carbonic acids, have been reduced to aldehydes in moderate yields with disodium tetracarbonylferrate Na2Fe(CO)4. Heating a carboxylic acid, presumably to form the anhydride, and then reaction with Na/EtOH leads to the aldehyde. 

Diethyl cyclopropane-1,1-dicarboxylate underwent a nucleophilic ring-opening reaction with disodium tetracarbonylferrate in which one of the carbon monoxide ligands acted as a C-nucleo-phile. The intermediate iron complex reacted with electrophiles such as protons or iodomethane to give y-oxopropanedioates. ... 

An alternative route to aldehydes from carboxylic acids involves conversion of the acid into the carboxylic ethylcarbonic anhydride (1) by reaction with ethyl chloroformate. These anhydrides react with sodium tetracarbonylferrate... 

Hydroacylation of Michael acceptors. The organotetracarbonylferrates obtained by alkylation of disodium tetracarbonylferrate undergo insertion reactions with Michael-type acceptors to give eventually y-keto esters, ketones, and nitriles. The last example shows an interesting synthesis of a cyclopentanone by an intramolecular insertion reaction. ... 

In contrast, the highest recorded yield of the thermal reaction with disodium tetracarbonylferrate was a meagre 32%, described by Emerson et al. [279]. 

Reaction of disodium tetracarbonylferrate with 2 equiv. of a chlorophosphirene resulted in coupling of two of the phosphirine units and complexation to Fe(CO)4 (Scheme 48). Subsequent reaction with diiron nonacarbonyl gave the di-complexed phosphirene. ... 

The initial reaction between the alkyl halide (or p-toluenesulfonate) and disodium tetracarbonylferrate behaves as a typical Sn2-type substitution. Thus this step proceeds smoothly with primary and secondary reactants, but the tertiary analogs fail... 

Nonacarbonyldiiron in the presence of activated zinc as well as disodium tetracarbonylferrate have both been utilized to dechlorinate dimethyl cispransjransA,2,3,4-tetrachlorocyclobutane-1,2-dicarboxylate (41), which leads to [dimethyl l,2,3,4- 7-l,3-cyclobutadiene-l,2-dicarboxy-latejiron tricarbonyl (42) in 1 and 35-40% yield, respectively.15 As a result of the better leaving tendency of the bromide anion, the yield of 42 can be improved to 70% by reaction of the analogous dibromide with nonacarbonyldiiron in dimethylformamide.16 In another experiment, debromination with activated zinc in tetrahydrofuran converts cyclobutane-1,2-di-carboxylate 43 to cyclobutene-1,2-dicarboxylate 44 in 58% yield.15... 

When aldehydes, with or without a hydrogen, are treated with aluminum ethoxide, one molecule is oxidized and another reduced, as in 9-69, but here they are found as the ester. The process is called the Tishchenko reaction. Crossed Tishchenko reactions are also possible. With more strongly basic alkoxides, such as magnesium or sodium alkoxides, aldehydes with an a hydrogen give the aldol reaction. Like 9-69, this reaction has a mechanism that involves hydride transfer.751 The Tishchenko reaction can also be catalyzed752 by ruthenium complexes.753 by boric acid,754 and, for aromatic aldehydes, by disodium tetracarbonylferrate Na2Fe(CO)4,755 OS I, 104. 

The reaction of halides (e.g., 8) with iron pentacarbonyl, base, and tet-rabutylammonium bromide as the catalyst has been reported to give ketones (e.g., 9) and variable amounts of hydrocarbons (e.g., 10). The latter was the major product formed at low base concentration while the ketone was the exclusive or predominant product at high base concentration (24). The tetracarbonylferrate(II) species, Fe(CO)42, is the supposed reagent... 

The reaction of l-chloro-17/-phosphirene 4 with disodium tetracarbonylferrate leads to selective formation of monocomplexed bi-l/7-phosphirene 6, which is converted into the doubly complexed species 7 upon treatment with diiron nonacarbonyl (Scheme 4) <2001EJI2067>. 

To circumvent the difficulty, we attempted to start from other a-C-metallated keto compounds. Thus, we prepared acetonyltetracarbonylferrate by the reaction of disodium tetracarbonylferrate tCaution pyrophoric ) with chloroa-cetone in THF according to literature data (Ref. 121). Phosgenation in situ afforded isopropenyl chloroformate but in very variable and non-reproducible yields not exceeding 50 % as depicted in scheme 94 (Ref. 122). 

Applications of carbonylaie reactions in organic synthesis are numerous. Particularly noteworthy are schemes involving tetracarbonylferrate( - ID (referred to as Collman s reagent), which can be isolated as a. sodium salt, NanFe(CO)4-1.5 dioxane, and is commercially available. The highly nucleophilic [Fe(CO)4p reacts readily with alkyl halides to yield alkyl iron carbonylates ... 

Inversion of configuration (cf Epimerization) of alcohols (Mitsunobu reaction), 160-161, 286 of ally lie acetates with Pd, 27, 164 of allylpalladium with d-synthons, 27, 264 of alkyl halides or sulfonates by 1,3-dithiane anions, 22 by organylcuprates, 36 by tetracarbonylferrate<2 -X 46-47 in triorganylborane rearr., 37-38 of glycosides with free 2-OH by DAST, 272 of glycosyl halides, 271 of oxiranes by 1-alkync anions, 64, 204 by enolate type anions, 63-64 by internal alcoholate addition, 265 Inversion-esterification of alcohols, 160-161, 286 Inverted DNA , 345-346 Iodide, hydrogen porphyrin synthesis with, 255 Iodine = diiodine (Ij) ... 

Pentane (200 mL) is added by cannula to the reaction mixture, which is then stirred for an additional 30 min before the flask is tilted and its contents filtered under a positive pressure of nitrogen through a coarse-frit glass disk filter. The collected snow-white precipitate of Na2[Fe(CO)4] is rinsed with two 100-mL portions of pentane, and the flask is transferred to the dry box, where the contents are dried under vacuum (0.1 torr) for 4 hr to give 7.39 g [96%t based on Fe(CO)s] of disodium tetracarbonylferrate(2-).t Approximate elapsed time... 

In contrast to the usually expensive organo transition metal complexes, sodium tetracarbonylferrate(-II) is inexpensive and versatile. E.g. aldehydes and unsym. ketones can be synthesized from halides and tosylates in high yields with this reagent Thallic nitrate converts acetophenones directly into methyl phenylacetates. Where applicable this new method is more convenient than the rather tedious Willgerodt-Kindler reaction... 

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. ... 

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. 

Reaction of the tetracarbonylferrate dianion with a dichlorosilane in the presence of HMPA also produced base-stabilized silylene complexes (Equation (29)), but the donor group could also be intramolecularly bound (Scheme 15). 

In addition to dihalides such as 2, other organohalides can serve as precursors for the synthesis of trimethylenemethane complexes by dehalogenation. This dehalogenation can be afforded not only by iron carbonyls but also by disodium tetracarbonylferrate(-II). For example, the reaction of 2-(bromomethyl)allyliron halide 6 with Fe2(CO)g afforded trimethylenemethane complex 3 in 91% yield (Scheme 10.3) [16]. 

Aryl and thiolic esters react with disodium tetracarbonylferrate to give aldehydes in moderate yields. However, long reaction times are required, and the reaction is not applicable to alkyl esters (Watanabe et al, 1976b). 

Alkylation of disodium tetracarbonylferrate with alkyl halides and tosylates in the presence of ethylene provides ethyl ketones in a one pot procedure. Usage of alkenes for the second alkylation of Collman s reagent may provoke rearrangement reactions of the intermediate alkyliron species. This has been observed in a hexacyclic system where a ketone with a rearranged carbon skeleton was obtained in the course of this transformation. An analog of Collman s reagent is the [Fe(CO)3(NO)] anion, which can be applied in similar reactions. However, to date it has received less attention. ... 

Methoxy(aryl)carbene]iron complexes are obtained by reaction of the appropriate benzoic chlorides with [Fe(C5Mes)(CO)2]K to give the acyliron complexes, followed by methylation with methyl mesylate. Reduction with sodium borohydride and removal of the methoxy group by treatment with trimethylsilyl triflate affords the defunctionalized (arylcarbene)iron complexes. The presence of ortAo-methoxy or ortho-chloro substituents at the arene moiety gives rise to (T) -C,OMe) or (T1 -C,C1) chelate (arylcarbene)iron complexes upon irradiation. Disodium tetracarbonylferrate reacts with aromatic (V,A -diallylamides followed by treatment with trimethylsilyl chloride with direct formation of chelated a-aminocarbene complexes (Scheme 4-59). ... 

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