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1985 (1)
1Author    JohnJ. Eisch, AndrzejM. Piotrowski, AllenA. Aradi, Carl Krüger, MariaJ. Romão, D. Ruhr, F.R GRequires cookie*
 Title    Die oxidative Addition von NickeI(0)-KompIexen an Kohlenstoff-Kohlenstoff-Bindungen im Cyclobutadien. Zur Frage der Überführbarkeit von CycIobutadien-Nickel(O)-Komplexen in Nickelaringe* Oxidative Addition of Nickel(O) Complexes to Carbon-Carbon Bonds in Cyclobutadiene. The Question of the Interconvertibility of Cyclobutadiene-nickel(O) Complexes and the Nickelaring Systems  
 Abstract    Bis(triethylphosphine)(?7 4 -tetraphenylcyclobutadiene)nickel (4) was synthesized by the reduc-tion of (?7 4 -tetraphenylcyclobutadiene)nickel(II)bromide (3) with r-butyllithium in the presence of Et 3 P, and its structure was determined by X-ray crystallography. Furthermore, its reactivity towards CO, CH 3 C0 2 H, PhC=CPh, LiAlH 4 and 0 2 were investigated. l,l-Bis(triethylphos-phine)-2,3,4,5-tetraphenylnickelole (14) was synthesized from (E,E)-1,4-dilithio-l,2,3,4-tetraphenyl-l,3-butadiene (15) and bis(triethylphosphine)nickel(II)bromide. Since the resulting crystals of the nickelole were not suitable for X-ray structure determination, the compound was characterized by elemental analyses, spectral data and carbonylation to yield tetraphenylcyclo-pentadienone (6). Analogous reductions of (?; 4 -tetraphenylcyclobutadiene)nickel(II)bromide (3) in the presence of Ph 3 P or Ph 2 PCH 2 CH 2 PPh 2 , followed by carbonylation, led to 6 in 40% yield, demonstrating that about half of the cyclobutadiene rings in 3 undergo cleavage upon reduction to give the nickelole. Reactions of the dilithium reagent 15 with NiBr 2 complexed with Me 2 PCH 2 CH 2 PMe 2 , Ph 3 P or Et 2 PCH 2 CH 2 PEt 2 , led to the formation of thermolabile nickeloles, as demonstrated by carbonyla-tion which yielded 6. Warming of the nickeloles and subsequent treatment with CH 3 C0 2 H led to the formation of l,2,3,4,5,6,7,8-octaphenyl-l,3,5,7-octatetraene (8) and, in one case, octaphenyl-cyclooctatetraene (5). The relevance of these findings to the mechanism of the Reppe nickel-catalyzed oligomeriza-tion of alkynes is discussed. 
  Reference    Z. Naturforsch. 40b, 624—635 (1985); eingegangen am 15. Januar 1985 
  Published    1985 
  Keywords    Insertion Reaction, Oxidative Addition, Cyclobutadiene-Nickel(O) Complexes, Nickelacyclopentadiene, Nickelole 
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 TEI-XML for    default:Reihe_B/40/ZNB-1985-40b-0624.pdf 
 Identifier    ZNB-1985-40b-0624 
 Volume    40