Rieke nickel

Perfluoroalkyl or -aryl halides undergo oxidative addition with metal vapors to form nonsolvated fluonnated organometallic halides and this topic has been die subject of a review [289] Pentafluorophenyl halides react with Rieke nickel, cobalt, and iron to give bispentafluorophenylmetal compounds, which can be isolated in good yields as liquid complexes [290] Rieke nickel can also be used to promote the reaction of pentafluorophenyl halides with acid halides [297] (equation 193)... 

Preparation of Rieke Nickel, Characterization of Active Nickel Powder, and Some Chemistry... 

Rieke Ni-promoted (Scheme 11) and cat. NiCk/Mg/MesSiCl-mediated pinacol coupling have been investigated [38]. The similar nickel-catalyzed reaction was also reported later [39]. 

T.A. Chen and R.D. Rieke, The first regioregular head-to-tail poly(3-hexylthiophene-2,5-diyl) and a regiorandom isopolymer nickel versus palladium catalysis of 2(5)-bromo-5(2)- (bromozincio)-3-hexylthiophene polymerization, J. Am. Chem. Soc., 114 10087-10088, 1992. 

Transition metal-catalyzed polymerizations have been reported to give high-purity, regioregular poly-3-alkylthio-phenes suitable for use in electronic devices. Thus, the Negishi protocol using a nickel catalyst and Rieke zinc was employed for the polymerization of 63 to produce the product as a low molecular weight polymer <2003CC2548>. 

The majority of synthetic approaches to binary carbonyls involve car-bonylation of solutions of metal salts in the presence of a suitable reduc-tant (Figure 3.11). Nickel and iron are the only metals that will react readily with CO, and even iron requires the use of high temperatures (420 K) and pressures (100 atm). Some other metals (Mo, W, Co, Ru) in highly activated form ( Rieke metals ) will also react with CO under higher temperatures and pressures. 

Rieke and coworkers have found that a special type of activated metallic nickel, available through reduction of nickel(II) iodide with lithium metal, suffers oxidative addition of benzylic and allylic halides. The resulting nickel(Il) complexes readily undergo cross-coupling with acid chlorides to form ketones. Once again it was difficult to obtain, y-unsaturated ketones from this method. Moderate to good yields of simple ketones may be prepared by this method. 

Inaba, S., Rieke, R. D. Reformatskii type additions of haloacetonitriles to aldehydes mediated by metallic nickel. Tetrahedron Lett. 1985, 26, 155-156. 

Inaba, S. and Rieke, R. D. 1985. Metallic nickel-mediated synthesis of ketones by the reaction of benzylic, allylic, vinylic, and pentafluorophenyl halides with acid halides. /. Org. Chem. 50 1373-1381. 

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