Palladium complexes cyclo-octatetraene

In 1953 Jensen llfl) reported that the reaction between cyclo-octatetraene and K2(PtCl4) produced the complex (C8H8)PtCl2. He likewise described the iodo derivative, (C8H8)Ptl2. A tub conformation was postulated for the cyclooctatetraene ligand in these structures. Subsequent, detailed, infrared and NMR studies of these and analogous palladium complexes indicate substantial x-electron delocalization t05). 

Ring-contraction of cyclo-octatetraene to phenyl acetaldehyde is catalysed by copper(i), platinum(ii), palladium(ii), and silver(i) complexes. Cycloheptatriene alde--hyde was detected during the copper(i) rearrangement. ... 

Cyclobutene (94) undergoes ring expansion to (95) on reaction with (Me3N)3PO and sodamide palladium chloride complexes of tetrasubstituted cyclobutadienes give octasubstituted cyclo-octatetraenes on reaction with triphenylphosphine. ... 

As found for palladium, c/r-dialkyl complexes can be prepared using a variety of chelate ligands such as Et2PCH2CH2PEt2, EtSCH2CH2SEt and olefins such as norbornadiene,cyclo-octa-l,5-diene and cyclo-octatetraene,... 

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