Amines alkene-iron complexes

Cyclic imides are accessible by a similar methodology. Reaction of dodeca-carbonyltriiron with primary amines gives an amine(carbonyl)iron complex that reacts with an alkyne under double carbonyl insertion to a ferracycle. Treatment of this complex with an excess of primary amines leads to a nucleophilic attack of the amine at the carbonyl function displacing the carbonyliron moiety presumably under formation of an alkene(hydrido)iron complex that may reduce the carbonyl groups to hydroxy groups. 

Scheme 9 that both the molybdenum and iron complexes can catalyze the allylic amination of nonfunctionalized alkenes with an ene-like transposition of the double bond, but also that the yield of the allyl amine formed, 113, is moderate to high. It is generally found that higher substituted alkenes tend to give the best yields, and un-symmetrical alkenes (trisubstituted) react with virtually complete regioselectivity, as only one isomer is detected. The byproducts are primarily azoxybenzene and aniline, which arise from condensation of nitrosobenzene with phenyl hydroxylamine and reduction of phenyl hydroxylamine, respectively. 

Mechanistically related to Mn, is the use of Fe as an epoxidation catalyst. Recently, iron complexes with a tetradentate amine core were reported, that were capable of activating H202 without the involvement of hydroxyl radicals [72]. For a variety of substituted as well as terminal alkenes, effective epoxidation... 

Palladium-catalyzed methylene transfer from diazomethane has proved effective for the cyclopropanation of 1-alkenylboronic acid esters allylic alcohols and amines 1-oxy-l,3-butadienes and allenes " Readily accessible iron complex (CO)2FeCH2S Me2 BF4 35 undergoes direct reaction with a range of alkenes to give cyclopropanes (equation 67) The salt is sensitive to steric effects and the reaction proceeds... 

Addition of a variety of nucleophiles to rf-alkene and alkyne ligands has been investigated, particularly when these ligands are complexed with iron and palladium. Reactions shown in equation 8.39 demonstrate well the typical stereochemistry resulting from the trans mode of attack by external nucleophiles on t 2—7t systems.56 Careful analysis of the reaction of amines with ( )- and (Z)-2-butenyl iron complexes (the CpFe(CO)2 group is abbreviated Fp, which is pronounced fip ) showed the stereochemistry to be cleanly anti.51... 

S. Davies has used an iron complex as an auxiliary for the asymmetric cyclopro-panation of a,P-unsaturated carbonyls [105]. The iron acyl is most stable in the s-cis conformation, as illustrated in Scheme 6.27, in order to avoid severe interactions between the iron ligands and R. Coordination of the Simmons-Smith reagent to the carbonyl oxygen, anti to the iron, forces the alkene moiety out of conjugation and approximately orthogonal to the carbonyl. Because of the bulky triphenyl phosphine in the rear, this rotation can only be towards the front. Transfer of the methylene via the illustrated transition state accounts for the observed diastereoselectivity. Oxidation with bromine removes the iron acyl and derivatization with a-methyl-benzyl amine allowed evaluation of the stereoselectivity. 

These Fp-alkene complexes react with a variety of other nucleophiles,3 5 including water, alcohols, amines,3 6 phosphines, and thiols as well as carbon nucleophiles (enamines, organocuprates, enolates),3 2,3l8 and dialkyl cadmium reagents.3 9 Diene complexes such as 487 were converted to the corresponding cationic complexes (488), for example, and reaction with malonate gave 489. The iron complex was removed with trimethylamine N-oxide (Me N-O) to give 490.320... 

In alkaline solution of an iron-carbon monoxide complex, the alkenes are converted into aldehydes and finally alcohols of one more carbon atom. Under these conditions, the iron complex of carbon monoxide was found to be binuclear, whereas the mononuclear complex is labile at temperatures above 140°C. In addition, it has been found that aldehyde is an initial product that is reduced to alcohol in the second stage of the reaction, and the nature of the base plays an important role in controlling the reaction path, either to produce aldehyde (e.g., KOH) or alcohol (e.g., alkyl amines).The formation of aldehyde is known as Reppe hydroformylation or the Reppe reaction. ... 

Aziridination of Alkenes. Iron- and manganese-porphyrin corrqilexes catalyze the reaction of PhI=NTs with alkenes to form the corresponding fV tosylaziridines. Mn(TPP)Cl is generally a better catalyst than the analogous iron complex, affording 80% of the aziridine from the reaction with styrene (eq 11). Good yields are also obtained in the manganese-catalyzed reactions with 1,1-and l,2-diphenylethylenes. Yields of aziridines derived from aliphatic alkenes remain low and are complicated by the formation of allylic amines. 

Cationic alkene-Fp complexes are rather stable and easier to handle than their neutral alkene(tetracarbonyl)iron congeners. Due to their positive charge, they are inert towards electrophiles and, thus, can be employed as protecting groups for olefins. Bromination and hydrogenation of other double bonds in the molecule leaves them unaffected. On the other hand they readily react with various nucleophiles such as enamines, enolates, silyl enol ethers, phosphanes, thiols, and amines to give alkyl-Fp... 

Reaction of ferralactone complexes with amines provides ferralactam complexes. Aromatic amines require the addition of a Lewis acid, whereas alkyl amines react spontaneously. In the course of the reaction, the iron complex moiety moves from one end of the allyl system to the other with concomitant inversion of the configuration at Cl and C4. Reaction of a tricarbonyl(vinylketene)iron complex with electron-deficient alkenes gives (pentenediyl)iron complexes that can be oxidized to tetrasubstituted cyclopropanes. ... 

The bleomycins (50) are hardly simple amines, but they do have two NH2 groups and a CONH2 group at the N-terminal domain, as well as potential donor nitrogens in pyrimidine and imidazole, which can complex metal ions." " The complexing of iron to bleomycin" " " has a significant effect on bleomycin-DNA interactions—metal complexes can mediate strand scission—and on alkene oxidation. Both may involve hydroperoxide intermediates." " " " ... 

Nitrogen nucleophiles such as amines (and in intramolecular cases, amides and tosamides) readily add to alkenes complexed to palladium(ll) and iron(ll) with reactivity and regiochemical features parallel to those observed for oxygen nucleophiles. However, these metal-assisted animation reactions are subject... 

Aviv and Gross developed an interesting insertion reaction of diazo compounds into a secondary amine-hydrogen bond in the presence of Fe-corrole complexes (Scheme 7.8) [12], Competition experiments performed in the presence of an amine and an alkene revealed the N—H-insertion reaction to be much faster than the cyclopropanation of the C=C bond. Apart from this chemoselectivity issue, the reactions are characterized by their very short reaction times most insertion reactions were completed within 1 min at room temperature. Most recently, Woo s group reported on a similar process using commercially available iron tetraphenyl-porphyrin [Fe(TPP)] dichloride [13]. 

Bis(phosphoranimine) ligands, chromium complexes, 5, 359 Bis(pinacolato)diboranes activated alkene additions, 10, 731—732 for alkyl group functionalization, 10, 110 alkyne additions, 10, 728 allene additions, 10, 730 carbenoid additions, 10, 733 diazoalkane additions, 10, 733 imine additions, 10, 733 methylenecyclopropane additions, 10, 733 Bisporphyrins, in organometallic synthesis, 1, 71 Bis(pyrazol-l-yl)borane acetyl complexes, with iron, 6, 88 Bis(pyrazolyl)borates, in platinum(II) complexes, 8, 503 Bispyrazolyl-methane rhodium complex, preparation, 7, 185 Bis(pyrazolyl)methanes, in platinum(II) complexes, 8, 503 Bis(3-pyrazolyl)nickel complexes, preparation, 8, 80-81 Bis(2-pyridyl)amines... 

Further evidence for the involvement of 116 in the amination reaction comes from the isolation of the related alkene complex 122 which by heating in dioxane solution gives allyl amine 117 (Eq. (28)). The latter results for the iron chlorides indicate an on-metal process with the ene reaction taking place in the sphere of the iron center, with both the nitroso and alkene compound coordinated to the sphere of the metal [64c,d]. 

Nucleophilic attack on ( -alkene)Fp+ cations may be effected by heteroatom nucleophiles including amines, azide ion, cyanate ion (through N), alcohols, and thiols (Scheme 39). Carbon-based nucleophiles, such as the anions of active methylene compounds (malonic esters, /3-keto esters, cyanoac-etate), enamines, cyanide, cuprates, Grignard reagents, and ( l -allyl)Fe(Cp)(CO)2 complexes react similarly. In addition, several hydride sources, most notably NaBHsCN, deliver hydride ion to Fp(jj -alkene)+ complexes. Subjecting complexes of type (79) to Nal or NaBr in acetone, however, does not give nncleophilic attack, but instead results rehably in the displacement of the alkene from the iron residue. Cyclohexanone enolates or silyl enol ethers also may be added, and the iron alkyl complexes thus produced can give Robinson annulation-type products (Scheme 40). Vinyl ether-cationic Fp complexes as the electrophiles are nseful as vinyl cation equivalents. ... 

When metal ion complexed amino radicals are produced by the reaction of A -chloro amines with reducing metal salts in the presence of alkenes, /6-halo amines are produced12-39 41. The reaction of 1-chloropiperidine with cyclohexene, iron(II) sulfate and iron(III) chloride in methanol afforded mainly the d.s-adduct of 2. The diastereoselectivity is attributed to coordination of the unprotonated amino group with the iron(III) salt, which is mainly responsible for the chlorine atom transfer. With A-chlorodimethylarnine and 4-chloromorpholine lower yields are obtained. 

Stoichiometric experiments were conducted with the functionalized alkenes to further explore iron-substrate interactions and gauge relative coordination affinities. Several bis(imino)pyridine iron amine and ketone compounds were isolated and studied using a combination of X-ray diffraction, NMR and Mossbauer spectroscopy and established electronic structures similar to that for ( PDI)Fe(N2)2-In the absence of H2, diallyl ether and allyl ethyl ether underwent facile C-0 bond cleavage and yielded a near equimolar mixture of the corresponding iron allyl and alkoxide complexes [89]. Our group has recently published a comprehensive study on these types of reachons and discovered rare examples of C-0 bond cleavage in saturated esters [89]. 

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