Eight coordination, attack

Telomerization reactions, the formation of short oligomers from dienes, represent a very efficient organic transformation with an overall atom economy of 100%, and they have been the subject of intensive research in both academic and industrial laboratories. Complexes of palladium are known to catalyze the reaction of dienes with a variety of nucleophiles. Mechanistically, the reactions are thought to proceed by allyl coordination of two butadiene molecules to a palladium(O) center followed by the formation of a C-C bond. The eight-carbon chain is then attacked by a nucleophile at the terminal or at the 3 position. The reaction usnally leads to a mixture of cis/trans isomers and n- and iio-prodncts. When the nncleophile is methanol, l-methoxyocta-2,7-diene 1 (n-product) is generally the major prodnct, which is a nseful precnrsor for plasticizer alcohols (octanols), solvents, corrosion inhibitors, and monomers for polymerization. ... 

All noble gas compounds (except for proton adducts such as the gas-phase species HeH" ") are hypervalent that is, they have more than eight eleeflons in the noble gas valence shell. In addition, XeF4 and XeF are susceptible to nucleophilic attack by F , which further increases their coordination number. Fluoride ligands are also common leaving or migrating groups in much of xenon chemistry. 

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