Ferrocene derivative reactions

Other interesting synthetic applications of the ketone-derived enamine alkylation are found in the monomethylation of steroid enamines (249), extension of the benzylation reaction (250) to a ferrocene derivative (251), the use of a-bromoesters (252) and ketones (252) or their vinylogues (25J), in the syntheses of alantolactone (254-256), isoalantolactone (257), and with a bridged bis-enamine (258). The use of bifunctional alkylating agents is also seen in the introduction of an acetylenic substituent in the synthesis of the characteristic fragrant constituent of jasmine (259), the synthesis of macrocyclic ketolactones (260), the use of butyrolactone (261), and the intermolecular or intramolecular double alkylations of enamines with dihalides (262). 

RELATIVE REACTIVITIES OF REACTION OF FERROCENE DERIVATIVES WITH MeCOCl... 

III. SELECTIVE ION TRANSFER AT THE W/0 INTERFACE COUPLED WITH REDOX REACTIONS BETWEEN FLAVIN MONONUCLEOTIDE IN W AND A FERROCENE DERIVATIVE IN O AND CO2 EVOLUTION [19,21]... 

Better yields are obtained when polar solvents are utilized and an amine such as tetramethylethyl-enediamine is present, which also facilitates the formation of the dilithium compound. The lithium derivatives undergo a large number of reactions that can be used to produce the enormous number of ferrocene derivatives. Rather than trying to show a great number of reactions, a few of the common reactants and the substituents that they introduce on the cyclopentadienyl rings are shown in Table 21.3. 

Another derivative that is a useful intermediate for synthesizing other derivatives is the mercury compound that can be prepared from ferrocene by reaction of mercuric acetate in a solution also containing chloride ion. 

Borate esters react with the lithium compound to yield (r/ -cp)Fe(r 5-cp-B(OR)2), which can be hydrolyzed to produce (//5-cp)Fe(r/5-cp-B(OH)2). This compound will undergo many reactions that lead to additional ferrocene derivatives. For example, the reaction with CH3ONH2 produces the aminoferro-cene. The boric acid derivative will react with AgO in a coupling reaction that produces the "diferrocene" shown as... 

While Josiphos 41 also possessed an element of atom-centered chirality in the side chain, Reetz reported a new class of ferrocene-derived diphosphines which had planar chirality only ligands 42 and 43, which have C2- and C -symmetry, respectively.87 Rhodium(i)-complexes of ligands (—)-42 and (—)-43 were used in situ as catalysts (0.75 mol%) for the hydroboration of styrene with catecholborane 1 for 12 h in toluene at — 50 °C. The rhodium/ i-symmetric (—)-43 catalyst system was the more enantioselective of the two - ( -l-phenylethanol was afforded with 52% and 77% ee with diphosphines (—)-42 and (—)-43, respectively. In both cases, the regioselectivity was excellent (>99 1). With the same reaction time but using DME as solvent at lower temperature (—60 °C), the rhodium complex of 43 afforded the alcohol product with an optimum 84% ee. 

As the latter were not easily accessible by chemical synthesis at that time, new methods of preparing these ferrocene derivatives were developed and introduced in 1969. It was then proved that the U-4CRs of chiral a-ferrocenyl-alkylamines can form diastereomeric a-aminoacid derivatives stereo-selectively, and it was further shown that after the reaction the a-ferrocenyl groups of the products can be replaced by protons, thus resynthesizing the chiral a-ferrocenyl-alkylamines simultaneously." Later, the development of this ferrocene chemistry was given up since such syntheses cannot form the products in sufficient quantity and stereoselective purity. ... 

Starting from the alcohols,/erroceno/ (Fe(C5H5)(C5H4-OH), Fc-OH) and l,T-ferro-cenediol (Fe(C5pl4-OH)2, Fc((3H)2), a series of new ferrocene derivatives has been prepared, in which the oxygen is directly connected with the ferrocene unit. The reactions... 

It is typical that the photorearrangement 57 - 58 proceeds readily.37 This seems to rule out the triplet state of the rearranging molecule 57, reasoning that the ferrocene part of the molecule would very probably act as a triplet quencher,35 as is the case with other ferrocene derivatives structurally able to undergo triplet photoreactions.36 On the other hand, the reaction 55 - 56 cannot be sensitized with acetophenone33 (ET = 73.6 kcal mole-1 32ft). 

Ferrocene-derived ligand (l ,S)-Josiphos, which is widely used for catalytic asymmetric hydrogenation reactions, is also a good catalyst for the asymmetric copper-catalyzed 1,4-addition. Reaction in f-BuOMe in the presence of 6 mol% of this ligand gives products with up to 98%. ... 

Trifan, D. S., and R. Bacskai The role of iron in carbonium ion reactions of ferrocene derivatives. Tetrahedron Letters [London] 1960/13, 1. 

We are currently carrying out further investigations with neutral ferrocene derivatives in an attempt to resolve the apparent disconnection between the effects of CB7 encapsulation on homogenous and heterogeneous electron transfer reactions rates. 

We studied electrochemically induced ET between a ferrocene derivative (FeCp-X) in single oil droplets and hexacyanoferrate(III) (Fe(III)) in the surrounding water phase the reaction system is schematically illustrated in Figure 11 [50,74], Tri-n-butyl phosphate (TBP) containing FeCp-X (ferrocene [X = H] or decamethylferrocene [X = DCM]), a fluorescent dye (perylene [Pe 0.5 mM] or 9,10-diphenylanthracene [DPA 10 mM]), and TBA+TPB (lOmM) is dispersed in an aqueous solution containing TBA+Cr, MgS04 (0.1 M), and potassium hexacyanoferrate(II) (Fe(II) 0.2 mM) with a 1 500 (oil/water) weight ratio as a sample emulsion. 

In the previous section, we demonstrated the micrometer droplet size dependence of the ET rate across a microdroplet/water interface. Beside ET reactions, interfacial mass transfer (MT) processes are also expected to depend on the droplet size. MT of ions across a polarized liquid/liquid interface have been studied by various electrochemical techniques [9-15,87], However, the techniques are disadvantageous to obtain an inside look at MT across a microspherical liquid/liquid interface, since the shape of the spherical interface varies by the change in an interfacial tension during electrochemical measurements. Direct measurements of single droplets possessing a nonpolarized liquid/liquid interface are necessary to elucidate the interfacial MT processes. On the basis of the laser trapping-electrochemistry technique, we discuss MT processes of ferrocene derivatives (FeCp-X) across a micro-oil-droplet/water interface in detail and demonstrate a droplet size dependence of the MT rate. 

The second topic of this chapter is the role of coordination compounds in advancing electrochemical objectives, particularly in the sphere of chemically modified electrodes. This involves the modification of the surface of a metallic or semiconductor electrode, sometimes by chemical reaction with surface groups and sometimes by adsorption. The attached substrate may be able to ligate, or it may be able to accept by exchange some electroactive species. Possibly some poetic licence will be allowed in defining such species since many interesting data have been obtained with ferrocene derivatives thus these organometallic compounds will be considered coordination compounds for the purpose of this chapter. 

There are some reports in the literature concerning the cleavage of bonds between silicon and an sp2-hybridized carbon in silylcyclopentadienyl compounds of type 4 (Section II.B). For example, equation 4697 shows hydrolytic fission in the reaction of a tris(trimethylsilyl) substituted ferrocene derivative with aqueous tetrabutylammonium fluoride. 

An alternative biosensor system has been developed by Hart et al. [44] which involves the use of the NAD+-dependent GDH enzyme. The first step of the reaction scheme involves the enzymatic reduction of NAD+ to NADH, which is bought about by the action of GDH on glucose. The analytical signal arises from the electrocatalytic oxidation of NADH back to NAD+ in the presence of the electrocatalyst Meldola s Blue (MB), at a potential of only 0Y. Biosensors utilising this mediator have been reviewed elsewhere [1,17]. Razumiene et al. [45] employed a similar system using both GDH and alcohol dehydrogenase with the cofactor pyrroloquinoline quinone (PQQ), the oxidation of which was mediated by a ferrocene derivative. 

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