Ferrocenium hexafluorophosphate

Ferrocenium hexafluorophosphate (48) and catecholboronbromide (49) (Figure 3.6) are efficient catalysts that have been tested in the cycloadditions of cyclic and acyclic dienes with a variety of dienophiles [48]. Catalyst 48 is less active than 49, but is less corrosive. 

Jahn combined the formation of the enolate 2-713 resulting from an intermolecu-lar Michael addition of 2-711 and 2-712 with a radical reaction (Scheme 2.157) [363]. The enolate 2-713 did not undergo any further transformations due to the lack of appropriate functionalities. However, after formation of a radical using a mixture of ferrocenium hexafluorophosphate (2-714) and TEMPO, a new reaction channel was opened which afforded the highly substituted cyclopentene 2-715a diastereoselec-tively. 

B = molybdocene(IV) dithiol (70b). The solitaire porphyrazines exhibited rich redox chemistry, and could be oxidized with ferrocenium hexafluorophosphate to yield the paramagnetic Mo(V) species H2[pz(A3B)], A = di -ferf-butyl phenyl, B = molybdocene(V) dithiol (72a) and H2[pz(A3B)], A = dipropyl, B = molybdocene(V) dithiol (72b), which were studied by EPR (Scheme 13). Additionally, 70a was centrally metalated with Cu(II), to form Cun[pz(A3B)], A = di-ferf-butyl phenyl, B = molybdocene(IV) dithiol (71), which was then oxidized to Cun[pz(A3B)], A = di-terf-butyl phenyl, B = molybdocene(V) dithiol (73) and its magnetic properties investigated. 

Controlled potential coulometry in correspondence to the first anodic process shows the consumption of a fractional charge (n 0.5 electrons), thus confirming the occurrence of chemical complications accompanying the electron removal. Isolation of the product obtained by chemical oxidation (by ferrocenium hexafluorophosphate) showed it to consist of the tetragold complex [Au4(/ -SC6H4CH3)2(PPh3)4](PF6)2, whose molecular structure is illustrated in Figure 25.20... 

A special case for such aza[60]fuUerene arylation is the reaction of 2 with a 25-fold excess of ferrocenium hexafluorophosphate at 150 °C in an argon atmosphere, which afforded the ferrocenyl-hydroaza[60]fullerene dyad 31 (Scheme 12.10) [23]. 

The same research group has recently reported that the oxidative homocoupling of chiral aroylacetic acid derivatives proceeds stereoselectively when the sodium enolate derived from 38 is oxidized with bromine (equation 21). Good stereoselectivity was also observed in the oxidative homo- and heterocoupUng reactions of the lithium eno-lates of chiral 3-phenylpropionamides with iodine, copper(II) pentanoate and ferrocenium hexafluorophosphate. ... 

The possibility that metallocenes might function as Lewis acids in Diels-Alder reactions was probed with ferrocenium hexafluorophosphate [184]. The answer is affirmative the cycloadditions studied include methacrolein, crotonaldehyde, and methyl vinyl ketone as dienophiles and butadienes and cyclopentadienes as diene components. Yields are in the range 60-80 % with reaction times of 3-36 h at 0 to 20 °C. Fair to good yields were also obtained in reactions of isoprene and cyclopentadiene with acrolein and methyl vinyl ketone in the presence of 1 % [Pd(PPh3)2(MeCN)2](BF4)2 (in CH2CI2, room temperature). Methyl acrylate resulted in low yields, and chiral modification with (5)-BINAP is reported to give the cycloadducts with modest enantioselectivity [164]. 

The oxidatively induced reductive coupling of methyl ligands to afford ethane from Pd(n) dimethyl complex 11 was reported in 2009 by Mayer and Sanford [68]. Treatment of dimethyl Pd(ll) complex 11 with ferrocenium hexafluorophosphate ([Cp2Fe]PF6 Fc" ), an outer-sphere, single-electron oxidant, led to the formation of ethane alruig with cationic Pd(ll) complex 13 (Fig. 6). Based on the electrochemical study of closely related h/s-mesityl Pd(ll) complex 7 (Fig. 4) [56], the observed ethane formation was proposed to proceed via initial single-electron oxidation of 11 to Pd(lll) complex 12. 

Dissolve the crude cobalt(II) complex in 15 mL acetonitrile. Add one equivalent of ferrocenium hexafluorophosphate (18) and stir the solution for 2 h (see Note 9). 

A variety of oxidants can transfer an electron from the cobalt center including bromine, selenium oxide, and lead oxide. Ferrocenium hexafluorophosphate provided the most mild conditions and no purification difficulties. 

Anilino)-substituted (cyclohexa-1,3-diene)iron complexes can be cyclized in the presence of various oxidants (e.g., very active manganese dioxide iodine in pyridine, " and ferrocenium hexafluorophosphate, " to give... 

The complete series of antiostatins A and B can be synthesized exploiting the oxidative cyclization of an appropriately substituted (Ti -cyclohexa-l,3-diene)iron complex in the presence of ferrocenium hexafluorophosphate for the construction of the carbazole framework (Scheme 4-129)P ° This class of carbazole alkaloids strongly inhibits the radical induced lipid peroxidation by acting as scavengers of oxygen-derived free radicals. 

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