Iron complexes 7 -/iodine

The iron-mediated synthesis of 2-oxygenated carbazole alkaloids is limited and provides only a moderate yield (11%) for the oxidative cyclization to 2-methoxy-3-methylcarbazole using iodine in pyridine as the reagent [90]. Ferricenium hexafluorophosphate is the superior reagent for the iron-mediated arylamine cyclization leading to 3-oxygenated carbazoles (Scheme 12). Electrophilic substitution of the arylamines 16 with the complex salt 6a leads to the iron complexes 17. Oxidative cyclization of the complexes 17 with an excess of ferricenium hexafluorophosphate in the presence of sodium carbonate affords... 

Electrophilic aromatic substitution of the 4-aminobenzofuran 1103 with the complex salt 602 afforded the iron complex 1109 in quantitative yield. Cyclization of the complex 1109 with concomitant aromatization was achieved by oxidation with an excess of iodine in pyridine at 90 °C in air to afford directly furostifoline (224) (688,689) (Scheme 5.179). 

Applying the pseudo-atom convention to the iron complex in Figure 8, the iodine atom is priority 1, the t1S-C5H3R2 ligand is priority number 2, the phosphorus atom is priority number 3, and carbon is priority number 4.15 When the iron is viewed from the side opposite the priority number 4, the sequence is 1,2,3 in the anticlockwise or 5 direction. The highest priority carbon in the cyclopentadienyl ligand, indicated by an asterisk, is designated with the R chirality symbol by application of the extended CIP sequence rule. 

Fig (10) The iron complex (80), prepared from methyl abietate (79) is converted to compound (81) utilizing standard organic reactions. It was converted to allylic alcohol (82) by treatment with iodine and potassium bicarbonate. The ketone (83) obtained from (82) undergoes aromatization on bromination and dehydrobromination. Yielding (84) whose transformation to lactone (87) is accomplished following the similar procedure adopted for the conversion of (68) to (74). It is converted to pisiferic acid (1) by treatment with aluminium bromide in... 

Doubly bridged trinuclear clusters may be oxidized or reduced, but the stability of the one-electron product depends on the identity of the bridging group and on the terminal ligands bonded to the metals. The iron complex [Fe3(CO)2(/u-S)(/Li-SR)Cp3], the structure of which has not been fully defined, oxidizes reversibly in two one-electron steps. The monocation was synthesized by iodine oxidation of the neutral species but apparently decomposes to [ Fe(CO)( i-SR)Cp 2] (Section III,E) 148). 

The dialdehyde 791 was prepared starting from the readily available 77 -CS2-iron complex 789 and propargyl aldehyde 788. Treatment of the resulting intermediate (l,3-dithiol-2-ylidene)-ionic complex 790 with iodine afforded the desired 2,6(7)-diformyl-TTF 791 (Scheme 118) <2000CEJ1199>. By analogy, tetraacetyl-TTF was also prepared using hexa-3-yne-2,5-dione <1996TL8861>. 

Rigid ligands bearing a bis-oxazoline skeleton 3.28 (R. = Ph, R = H, R" = Me) readily derived from (5)-phenylglycinol 1.60 (R = Ph, R = H) have been prepared by Corey and coworkers [780,851] and used to generate iron complexes. These complexes are formed in situ from 3.28, Fel3 and iodine, and they catalyze some highly selective Diels-Alder cycloadditions with cydopentene. 

Quinolinc-5-sulfonic acid, 8-hydroxy-iron complexes gravimetry, 524 metal complexes iodination, 418... 

Fishmeals have a high mineral content (100-220 g/kg), which is of value nutritionally since it contains a high proportion of calcium and phosphorus and a munber of desirable trace minerals, including manganese, iron and iodine. They are a good source of B complex vitamins, particularly choline, B12 and riboflavin, and have enhanced nutritional value because of their content of growth factors known collectively as the animal protein factor (APE). 

Anionic hydridoiron species undergo selective addition to a, -unsaturated earbonyl compounds in methanol to give reduction products (Noyori et al., 1972c). Under an atmosphere of carbon monoxide, carbonylation takes place. Methylmalonate is selectively obtained from acrylate by treatment of the reaction mixture with alcoholic iodine (Masada et al., 1970). The organo-iron complexes are readily acylated by treatment with alkyl iodides in an aprotic solvent (Mitsudo et al., 1974). 

In 1991, Valentine reported the use of an iron complex of the bis(2-pyridine-carboxamido)benzene ligand for epoxidation reactions of olefins using iodosylbenzene [39]. Interestingly, the reaction products were similar to those produced with either Fe(OTf)3 or Al(OTf)3 as catalysts. With this and other data, a mechanism involving electrophilic attack of the olefin by soluble iodine(III)-metal complexes was proposed (Scheme 10) [40]. 

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