Cyclo-Pentalene complexes

Treatment of 5,8-bis(trimethylsilyl)cyclo-octa-l,3,6-triene or 3,5,8-tris(trimethyl-silyl)cyclo-octa-l,3,6-triene with triruthenium dodecacarbonyl gave the pentalene complexes (352 X = H or SiMe ). Tricarbonyl(Ti-cyclo-octa-l,5-diene)ruthenium and tricarbonyl(T)-cyclo-octa-l,3-diene)osmium have been prepared. They react with trityl fluoroborate to give cyclo-octadienylium complexes [(CgHn)M(CO)3] which react with anionic nucleophiles to give neutral compounds, some of which... 

Intramolecular C-H insertion reactions of ( -cyclo-pentadienyl)dicarbonyliron carbene complexes can be used to prepare complex polycyclic compounds. Carbon-hydrogen bond insertion using an iron carbene was used as a key step in the synthesis of sterpurene and pentalene (Scheme 81). ... 

Gold chloride forms an unstable complex with cyclo-octatetraene at low temperatures. This decomposes at — 20°C to l,2-dichlorocyclo-octa-3,5,7-triene, which gradually cyclizes to (562). In an attempt to form pentalene-metal complexes, cyclo-octatetraene was reduced to a mixture of trienes and bicyclo [4,2,0] octadiene, which was then treated with substituent ruthenium carbonyls, affording a variety of complexes, including (563). °... 

SiMea)2 to give (pentalene)Ru3(CO)8 complexes have appeared. Reaction of substituted cyclo-octatetraenes with Ru3(CO)ia yields initially Ru2(CO)s derivatives, which may be carbonylated to give complexes of structure (108) low-temperature n.m.r. spectra are consistent with this, but on warming, isomer interconversion occurs by a twitching of the Ru2(CO)e moiety. ... 

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