Cyclopentadiene iron carbonyl derivatives

Reactions of acetylene and iron carbonyls can yield benzene derivatives, quinones, cyclopentadienes, and a variety of heterocycHc compounds. The cyclization reaction is useful for preparing substituted benzenes. The reaction of / fZ-butylacetylene in the presence of Co2(CO)g as the catalyst yields l,2,4-tri-/ f2 butylbenzene (142). The reaction of Fe(CO) and diphenylacetylene yields no less than seven different species. A cyclobutadiene derivative [31811 -56-0] is the most important (143—145). 

In similar investigative studies for bimetalhc single-source precursors, an iron indane derivative was synthesized by the reaction Na[(Cp)(CO)2Fe]0.5THF with BrIn[(CH2)3NMe2]2 in THF (Scheme 18)). The analogous Ni, Co, and Mn intermetallic complexes were also successfully prepared with either cyclopentadiene or carbonyl ligands. Photolysis of the indium-iron derivative [ Cp(CO)2Fe 2ln(CH2)3NMe2)2]... 

Cyclopentadiene and its derivatives react in an unusual manner with iron carbonyls. Reaction of cyclopentadiene with Fe(CO)s under conditions normal for the preparation of diene-iron tricarbonyl complexes produces the binuclear complex (XLIV) and cyclopentene rather than (XLV) (69, 70). 

Dihydro-lH-l,2-azaboroles derive from cyclopentadiene by the isoelectronic replacement of a C=C group by a BN moiety ". The neutral rings react in xs boiling Fe(CO)j without any other solvent to form red-brown iron-dihydro-1,2-azaborolyldi-carbonyl dimers as their cis and transisomers in 56% yield, or with CojfCOg in petroleum ether at 60-80°C to the half-sandwich complex (dihydro-1,2-azaborolyl)Co(CO)2 (40%). The CO group can easily be substituted by olefins ... 

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