Cyclopentadienyl iron dicarbonyl

The commercially available (tj5-cyclopentadienyl)iron dicarbonyl dimer 1 is the source of the carbonyl(//5-cyclopentadienyl)iron(L) moiety. Reductive or oxidative cleavage of 1 provides reactive monomeric species that may be converted into iron-acyl complexes as described in the following sections (see also Houben-Weyl, Vol. 13/9a, p208). 

Any interconversion in a sample may give rise to temperature-dependent NMR spectra. For example, the 13C NMR spectrum of dimeric cyclopentadienyl iron dicarbonyl is temperature dependent [114]. This was attributed to intermolecular exchanges of carbonyls and interconversion between cis and trans complexes. 

In > , >y -bis(cyclopentadienyl)iron dicarbonyl the <7-bonded ligand is easily attacked by HFA with conservation of the a bond. Photochemical treatment of 147 affords 146d, in which both cyclopentadienyl rings become n bonded (76). 

Carbodiimides also add to metal carbon bonds in metalorganic compounds. For example, cyclopentadienyl iron dicarbonyl 286 affords [2-f2] cycloadducts 287 with diphenyl- and... 

To make the reactive fulleride compound KeCeo in the Fe-Ceo synthesis, fullerenes and a slight excess of potassium were sealed in a glass tube under vacuum and heated for approximately four days at 250 °C. Both solid-state NMR and Raman spectroscopy were employed to determine that the KeCeo compound was in fact synthesized. The KeCeo product was then reacted in an inert atmosphere with cyclopentadienyl-iron-dicarbonyl-iodide (CpFe(CO)2l) in tetrahydrofuran (THF) to form the complex. The recovered product was dried in an inert atmosphere. Manipulations of air-sensitive materials were carried out in a glove box or using standard Schlenk techniques. THF was distilled just prior to use from sodium benzophenone ketyl. Ceo was obtained from Aldrich, and CpFeCCOjol was obtained from Strew. 

A slight variation of the [3-I-2] cycloaddition approach <1977ICA(25)165> has also been employed for the diastereoselective synthesis of the corresponding anti- and ry -iron-substituted 1,2-dithiolane 1-oxides 243 from 237, as a source of electrophilic disulfur monoxide, and 7] -allyl iron complex 242 (Scheme 39). The method was also tested with cyclopentadienyl iron dicarbonyl crotonyl complex 244 when four diastereomers 245-248 were generated in modest yields (35%) <19980M5534>. 

OTHER COMMENTS, used in organic synthesis as the diene in the Diels-Alder reaction producing synthetic alkaloids and camphors useful as the starting materials for synthetic prostaglandin, chlorinated insecticides, and formation of cyclopentadienyl iron dicarbonyl dimer also used in manufacture of resins. 

Fe(CO)4H2 Iron tetracarbonyl dihydride, 2 243 potassium salt, 2 244 sodium salts, 7 194, 197 [Fe(C204)3]K3-3H20 Potassium trioxalatoferrate(III), 1 36 FeC6Hs(CO)2l Cyclopentadienyl-iron dicarbonyl iodide, 7 110 FeC6H5(CO)2Na Cyclopentadi-enyliron dicarbonyl, sodium derivative, 7 112 [FeC6H5(CO)2]2 Cyclopentadi-enyliron dicarbonyl, dimer, 7 110... 

For example N-ethylmaleimide 62 is a popular reagent used to permanently block cysteine residues [107]. N-substituted maleimide bearing a cyclopentadienyl iron dicarbonyl moiety 63 was synthesized by Rudolf and Zakrzewski in 1994 [108]. 

The first step is a simple displacement of two molecules of carbon monoxide. In the second step the acidic hydrogen of 7r-bonded cyclopentadiene shifts to the iron atom to give w-cyclopentadienyliron dicarbonyl hydride, a known compound. Two molecules of this iron hydride then add hydrogen to cyclopentadiene to form cyclopentene and the dimer of w-cyclopentadienyl-iron dicarbonyl. This reaction proceeds at temperatures between 150° and 220° C. Above 220° C, the remaining carbon monoxide molecules are displaced by a second molecule of cyclopentadiene forming ferrocene [42). 

Methylcyclopentadiene readily undergoes reaction with metal carbonyls 47) and even 1,3-diphenylcyclopentadiene reacts with iron carbonyl 4S). A novel method for obtaining a ferrocene with one substituted ring, is the reaction of 1,3-diphenylcyclopentadiene with the dimer of cyclopentadienyl-iron dicarbonyl at 170° C to produce 1,3-diphenylferrocene in 15% yield. Other substituted cyclopentadienes which have been used are tetraphenyl-cyclopentadienone in the preparation of tetraphenyl(hydroxy)cyclopenta-dienylmanganese tricarbonyl 49) and indene in the preparation of the dimer of indenylmolybdenum tricarbonyl (50). A variety of substituted fulvenes have been used in the preparation of substituted cyclopentadienyl metal tricarbonyl compounds of Cr, Mo, and W (57, 52). This latter reaction proceeds best in the presence of a solvent, such as 1,2-dimethoxyethane, to permit easy abstraction of hydrogen. 

Ti-Cyclopentadienyl iron tricarbonyl cation is reduced by a hydride ion to form Ti-cyclopentadienyl iron dicarbonyl hydride, equation (6-20). In this case the jr-cyclopentadienyl ring remains intact. 

Fig. 47. The structure of ir-cyclopentadienyl iron dicarbonyl carboxymethyl dimer...

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