Iron complexes cyclopentadienyl carbonyls

In a similar manner, Jt-allyl complexes of manganese, iron, and molybdenum carbonyls have been obtained from the corresponding metal carbonyl halides [5], In the case of the reaction of dicarbonyl(r 5-cyclopentadienyl)molybdenum bromide with allyl bromide, the c-allyl derivative is obtained in 75% yield in dichloromethane, but the Jt-allyl complex is the sole product (95%), when the reaction is conducted in a watenbenzene two-phase system. Similar solvent effects are observed in the corresponding reaction of the iron compound. As with the cobalt tetracarbonyl anion, it is... 

Jiang S, Agoston GE, Chen T, Cabal M-P, Turns E (1995) BF3 Et20-promoted allylation reactions of allyl(cyclopentadienyl)iron(II) dicarbonyl complexes with carbonyl compounds. Organometallics 14 4697 -709... 

In this case (compare with Ref. 268), the Te — Te bond remains. This bond is not destroyed also under interaction of diphenylditellurides with cyclopentadienyl-carbonyl complexes of manganese (3.99a) [272] and iron (3.99b) [273] ... 

Aceto(carbonyl)cyclopentadienyl(triphenylphosphine)iron, CsHsFefCOKCOCH,)-[P(QHs)3] (1). Orange crystals, m.p. 145°, air stable. The chiral iron complex is prepared as a racemate by reaction of CsH5Fe(CO)2CH3 with P(C6H5)j. ... 

Fig. 12.2 (a) Line drawing of an acetyl(carbonyl)(cyclopentadienyl)(phosphine)iron complex, (b) Stereoview of the same molecule. [From Korp, J. D. Bernal, I. J. Organomet. Chem. 1981, 220, 355-364. Reproduced with permission.)... 

A chiral metal center, as is found in a pseudotetrahedral iron complex with cyclopentadienyl, carbonyl, triphenylphosphine, and ethyl ligands, has also been u,sed to address the question of alkyl migration versus carbonyl insertion. Inversion of... 

Decomplexation of carbonyl(t7 -cyclopentadienyl)(triphenylphosphane)iron complexes with cw-2-methylcyclopropanecarbonyl (1) with A-bromosuccinimide in ethanol gave ethyl cis-1-methylcyclopropanecarboxylate (2) in good yield. ... 

A very different, but similarly effective, auxiliary is the chiral carbonyl(t/5-cyclopentadienyl)(tri-phenylphosphine)iron moiety. When the z./i-unsaturated acyl-iron complex ( -)-(/ )-11 is treated by a modified Simmons Smith reagent, a 91 9 mixture of cyclopropane diastereomers is isolated in good yield73. Precomplexation of the starting iron complex by the Lewis acid zinc(II) chloride seems to be necessary to obtain good selectivity. The chiral iron moiety can then be removed oxidatively by bromine treatment, and the intermediate acyl bromides converted into amides by reaction with (/ )- -phenylethylamine. 

In spite of the differences in the electronic configuration of iron, cobalt, and nickel, the manner in which their respective carbonyls function as catalysts is essentially the same, differing only in detail. Under the proper conditions, for example, any of these metal carbonyls catalyze the reaction of acetylene, carbon monoxide, and alcohols to form acrylates. An iron complex, XI, in which most of the terminal carbonyls have been replaced by cyclopentadienyl groups, has been found to function, hke dicobalt octa-carbonyl, as a homogeneous hydrogenation catalyst 16) ... 

Optically active cyclopentadienyl iron complexes [Fecp(RO)(CO)L] were utilized for investigating the reaction mechanism of the alkyl ligand with the carbonyl group. It was found that migration of the alkyl group and the CO group both take place [see Section 4.12.b, equations (4.173) and (4.174)]. 

Miscellaneous. High-temperature and n.m.r. of [56 M = (Cp)Rh or Ma = (Cp)RhCu-H)Rh(Cp), X = CHaCHa M = (Cp)Rh, X = CHJ are consistent with one rearrangement process whereby only the metal-metal axis oscillates relative to the dienyl ring. The cyclopentadienyl signals, for instance, remain inequivalent at all temperatures. These results may be contrasted with those from similar iron complexes (56 M = Fe(CO)3, X = CHaCHg) where in the high-temperature limit all the carbonyls become equivalent. Thus at least one other... 

Ruthenium.— The oxidative addition of quinones to d and to metal centres is well documented. Now the oxidative addition of u-quinones to the d complex RuCl2(PPh3)3 has been reported. The reactions of ruthenium and iron cyclopentadienyl carbonyl dimers with azobenzene are described later (see manganese and rhenium). 

Thermolysis of the mononuclear (1,4-diphenyl-l-azabutadiene)iron complex 45 gives a diastereomeric mixture of the trinuclear complexes 46a and 46b, which are regarded as analogs of ferrocene with the ry -azaferracyclopenta-dienyl ligand 46. " Co-thermolysis of 45 with other metal carbonyl species produces heterodinuclear 77 -azaferra-cyclopentadienyl complexes 47 (Scheme 4). 

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