Palladium chemistry palladacycles

Herrmann WA, Brossmer C, Reisinger CP, Riermaier T, Ofele K, Beller M (1997) Coordination chemistry and mechanisms of metal-catalyzed C-C coupling reactions. Part 10. Palladacycles efficient new catalysts for the Heck vinylation of aryl halides. Chem Eur J 3 1357-1364 Iyer S, Jayanthi A (2001) Acetylferrocenyloxime palladacycle-catalyzed Heck reactions. Tetrahedron Lett 42 7877-7878 Iyer S, Ramesh C (2000) Aryl-Pd covalently bonded palladacycles, novel amino and oxime catalysts di- x-chlorobis(benzaldehydeoxime-6-C,AT)dipalla-dium(II), di- x-chlorobis(dimethylbenzylamine-6-C,A)dipalladium(II) for the Heck reaction. Tetrahedron Lett 41 8981-8984 Jeffery T (1984) Palladium-catalysed vinylation of organic halides under solid-liquid phase transfer conditions. J Chem Soc Chem Commun 1287-1289 (b) idem,... 

A variety of palladium(II) and palladium(O) complexes serve as effective precatalysts or precursors to the active palladium(O) catalyst. The most commonly used precatalysts in Heck chemistry are Pd(OAc)2, Pd2(dba)3, and PdCl2(PPh3)2. Typical catalyst loading is in the range of 5-10mol-%. The discovery of the unique catalytic activity of a dimeric palladacycle (Pd2(P(o-Tol)3)( Li-OAc)2) by Herrmann and Belle/ has set a milestone in palladium catalysis as it allows the use of even unreactive chloroaryl substrates intransformations. 

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