Diiron nonacarbonyl, reaction with

The strained-ring compound 1,1-dimethyl-l-silacyclobutane (which may be regarded as an olefin of organosilicon chemistry) reacts with diiron nonacarbonyl in benzene at 6°-20°C as shown in Eq. (100) (89). (There is here some analogy with the reactions of transition metal complexes with strained hydrocarbons, which often produce valence tautomerization.) The... 

The interaction of butadiynediyl dimetal complexes [Fp -C -CsC-M, Fp =FeCp (CO)2, M= Fp, Rp, SiMea, Rp= RuCp(CO)2] with diiron nonacarbonyl, Fe2(CO)9, results in the formation of a mixture of products, as is also observed in the case of their interaction with organic acetylenes. Interesting polymetallic complexes, propargylidene-ketene compounds, zwitterionic cluster compounds, and pa-p -propargylidene-cyclobutene compoimds were isolated from the reaction mixtures and successfully characterized. The product distributions were found to be dependent on the metal fragment (M) at the other end of the C4 rod. The results of the reaction are described... 

Formation of the reduced 1,3-oxazepine derivative 160 from the reaction of diiron nonacarbonyl with the tetrahydrooxazine derivative (159) involves a novel formal insertion of carbon monoxide into an N—O bond (Scheme 183).248 The synthetic applicability of this unusual reaction has not been evaluated. 

In 1987, Nitta reported the formation of an unexpected vinylketene complex from the reaction of an azido-substituted cyclopropene with diiron nonacarbonyl.104 They had previously investigated the chemical behavior of the complexed nitrene intermediates that result from the reaction of organic azides and iron carbonyls113 and were interested in replicating the thermal isomerization of 3-azido-l,2,3-triphenylcyclopropene (163) into 4,5,6-triphenyl-l,2,3-triazine using a metal carbonyl-promoted re-... 

The earliest alternative to cyclopropene insertion as a viable vinylketene synthesis was published by Hoffmann118 in 1972. Upon reaction of 206.a with diiron nonacarbonyl, the vinylketene complex 207 was isolated in low yield. The analogous bromide and iodide substrates formed the 77-allyl complexes 208, although a trace of 207 was isolated from the reaction of the bromide 206.b. 

Cycloproparenes do not form metal complexes with all transition metals. Reaction of cyclopropabenzene with diiron-nonacarbonyl yields polymer, while reaction with cyclopropanaphthalene leads to a stable product formed by metal and carbonyl insertion. Attempts to form cycloproparene-chromium complexes have also failed. ... 

The rearrangement occurs via the intermediate formation of 3-vinylcyclobutencs, which may be isolated, e.g. after treatment of the dichloro compounds with (nonacarbonyl)diiron, (nonacarbonyl)dicobalt or ethene[bis(triphenylphosphane)]nickel at room temperature.83 The straightforward method, however, seems to include both dechlorination and rearrangement, both reactions being promoted by (tetracarbonyl)nickel. 

Various substituted silacyclopentadienes react with iron or cobalt carbonyl compounds to give stable i 4-silacyclopentadiene complexes. Thus, with iron pentacarbonyl, reaction occurs at 150°-200° in an autoclave, with Fe2(CO)9 at 40°-60°, and with Fe3(CO)12 at 80° (20, 21, 49, 132) the same complex can be obtained from a dibromosilacyclopen-tene and diiron nonacarbonyl, under mild conditions (19) ... 

Several transition-metal complexes of cyclobutadiene have been prepared, and this is all the more remarkable because of the instability of the parent hydrocarbon. Reactions that logically should lead to cyclobutadiene give dimeric products instead. Thus, 3,4-dichlorocyclobutene has been de-chlorinated with lithium amalgam in ether, and the hydrocarbon product is a dimer of cyclobutadiene, 5. However, 3,4-dichlorocyclobutene reacts with diiron nonacarbonyl, Fe2(CO)9, to give a stable iron tricarbonyl complex of cyclobutadiene, 6, whose structure has been established by x-ray analysis. The 7r-electron system of cyclobutadiene is considerably stabilized by complex formation with iron, which again attains the electronic configuration of krypton. 

The expected monosilylene complex Fe(CO)4(83) (i.e., 105) was isolated in high yields from the reaction of diiron nonacarbonyl with compound 83, but reaction of Ru3(CO)i2 with silylene 83 gives the bissilylene complex Ru(CO)3(83)2 (i.e., 106) <2001JOM17>. 

Diene iron tricarbonyl complexes are prepared by thermal or photochemical reaction of conjugated dienes with iron pen-tacarbonyl in the presence of TMANO, triiron dodecacarbonyl, ()]" -benzylidenacetone)iron tricarbonyl, diiron nonacarbonyl, or diiron nonacarbonyl absorbed on silica gel in the absence of solvent. The latter method is particnlarly usefiil for the preparation of complexes from polar electron-rich dienes and heterodienes. A reductive complexation of cycloheptatrienes using iron tricarbonyl and sodium borohydride to give cyclo-heptadiene iron tricarbonyl has been developed (Scheme 126). 

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>. 

Cycloheptenones. Dehalogenation of z,x -dibromoketoncs with diiron nonacarbonyl in the presence of a 1,3-diene provides a direct route to seven-membered cyclic ketones. Thus the reaction of 2,4-dibromo-2,4-dimethylpentane-3-one (I), diiron... 

Cyclopenlenone synthesis. The reaction of a,a -dibromoketones with cnamines in the presence of diiron nonacarbonyl gives cyclopcnfenone derivatives in 50-100% yield. Thus the reaction of (I) with a-morpholinostyrene (2) with diiron nonacarbonyl as reducing agent gives the cyclopentenonc (3) in 94% yield. 

Other reagents recommended for the reduction of isoxazoles to 1,3-enaminoketones include samarium diiodide, molybdenum hexacarbonyl in aqueous acetonitrile, and diiron nonacarbonyl in water. Electrochemical methods have also been employed." A particularly mild method involves reaction with the reduced form of the coenzyme lipoamide (LA2) complexed with iron(II). Birch reduction (sodium and... 

The area of cyclobutadiene-transition metal chemistry has expanded rapidly since these initial findings, largely through the work of Maitlis 163), Nakamura 183), Freedman 104), and others, but details will not be presented here. Several recent important discoveries by Pettit and co-workers 22, 79,102, 24I), however, relate to the formation and chemistry of cyclobutadiene-iron tricarbonyl (XVII). This product is formed from the reaction of cis-3,4-dichlorocyclobutene and diiron nonacarbonyl and can be isolated in the form of yellow crystals of excellent stability. Cyclobutadiene can be liberated by treating the complex with oxidizing agents such as ferric or ceric ion. The free ligand has been trapped and demonstrated to possess a finite lifetime. It has also been shown to... 

First, cis- and trans-2-phenylmethylenecyclopropanes-3-d were shown to give trimethyl-enemethane complexes with the deuterium at a location consistent only with disrotatory ring-opening (Figure 41). Second, reaction of 2,2-diphenylmethylenecyclopropane with a variety of iron carbonyl reagents allowed isolation of the methylenecyclopropane iron tetracarbonyl complex. This compound could be shown to give the trimethylenemethane complex on reaction with trimethylamine-N-oxide or diiron nonacarbonyl, both of which... 

Cyclobutadiene itself has not been prepared, but the stable complex, cyclobuta-dieneiron tricarbonyl (3), can be prepared readily in quantities of 10 g. or more by reaction of 3,4-dichlorocyclobutene (1) with diiron nonacarbonyl (2).5... 

In a well-ventilated hood a 1-1. three-necked flask is immersed in an oil bath and fitted with a mechanical stirrer and condenser with aT-piece at the top with one lead connected to a nitrogen supply and the other to a gas bubbler. The flask is charged with 60 g. (0.49 mole) of c/i-3,4-dichlorocyclobutene (this volume) in 250 ml. of benzene, and the system is flushed with nitrogen. A first 50-g. batch of diiron nonacarbonyl (2) is added and the mixture is heated at 50-55° with stirring. After about 15 min. the initial rapid evolution of carbon monoxide becomes greatly diminished and a further 25 g. of Fe2(CO)9 is added. Further 25-g. portions are added until no more carbon monoxide is liberated a total of approximately 275 g. of Fe2(CO)9 is required and the total reaction time is about 5 hrs. The mixture is then filtered with suction through Celite and the Buchner funnel is washed thoroughly with pentane until the filtrate is colorless. Fractional distillation at reduced pressure removes benzene, then iron pentacarbonyl (b.p. 20730 mm.) when the Fe(CO)5 has been removed, cyclobutadieneiron tricarbonyl is collected as a pale yellow oil, b.p. 4773 mm. 

A mixture of 874 mg (2.40 mmol) of diiron nonacarbonyl, 918 mg (5.48 mmol) of 1-morpholinocyclohex-enc. and 510 mg (1.70 mmol) of 3,5-dibromo-2,6-dimethylhcptan-4-one in 5 mL of ben/.ene is heated at 32 JC with stirring for 12 h. The reaction mixture is diluted with 15 mL of EiOAe, then washed with 5 ml. of sat. NaHC03 followed by 5 mL of sat. NaCl. The organic layer is dried over Na,S04 and evaporated to give an oily material. This is treated with 3% ethanolic NaOH solution at 25 C for 10 min and quenched with water. The aqueous mixture is extracted with three 30-mL portions of EtOAc and then the organic extracts are dried. Removal of the solvents afforded an oil, which is subjected to preparative TLC (EtOAc/ hexane 1 10) to give the trans-product as colorless crystals yield 274 mg (73 %). Recrystallizalion produces an analytically pure sample mp 47-47.5 CC. 

The intramolecular mode of 4+3 cycloaddition reactions between allylic cations and dienes has been comprehensively summarized in several reviews. Nevertheless, the intramolecular 4+3 cycloaddition reactions are not as well established as the intermolecular ones. One of the very first examples of this reaction was reported in 1979 by Noyori and co-workers, who had previously studied the intermolecular reaction between polyhalogenated ketones and dienes. For instance, treatment of dibromoketones 27 or 28 with diiron nonacarbonyl in refluxing benzene provided cycloadducts 29 or 30 in 41% and 38% yields, respectively (Scheme 9). Although the stereoselectivities of these reactions were high, the lachrymatory nature of dibromoketones and the difficulty associated with the synthesis of dibromoketones limited the development of this process. Thus, no other examples of the intramolecular 4+3 cycloaddition using Noyori s methodology have been reported. 

Troponoids (5, 222-223). The reaction of a,a -dibromo ketones with diiron nonacarbonyl to generate an oxyallyl-Fe(II) species originally suffered one limitation only secondary and tertiary dibromo ketones reacted satisfactorily. For example, reaction of a,a -dibromoacetone, BrCH2COCH2Br, fails. Noyori et al. have presented a solution to this limitation. The reaction is carried out with a polybromo ketone and the bromine atoms in the adduct are removed with Zn-Cu couple. The synthesis of 8-oxabicyclo[3.2.11oct-6-ene-3-one (1) is... 

Reaction with thiobenzophenones. Treatment of thiobenzophenones (1) with diiron nonacarbonyl in benzene at 25° gives orilio-metalated complexes (2) in reasonable to high yield. The purple-red complexes are stable to air. One... 

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