Cyclooctatriene complexes with iron

Cyclooctatetraene (continued) with iron, 12 267-273 with nickel, 12 307, 308 with palladium, 12 315 with platinum, 12 319 with rhodium, 12 304 with ruthenium, 12 280 with silver, 12 340, 342, 343, 346 complexes of, 4 81 iron complexes of, 4 89 Cyclooctatriene complexes... 

A third product of the iron carbonyl-cyclooctatriene reaction is a red complex of formula CgHioFe2(CO)g, which was initially formulated as C9Hi2Fe2(CO)e (61). This is derived from the 1,3,5-isomer and probably has a bis(7r-allyl) structure like the corresponding complexes with cyclo-heptatriene (Section II, A) and cyclooctatetraene (Section III, B) (46, 90). 

An interesting reaction occurs in the case of the isomeric 1,3,5- and 1,3,6-cyclooctatrienes (XXXVI amd XXXVII). Fischer and co-workers (6J) reported that a mixture of these two hydrocarbons, when treated with iron carbonyl, gave rise to two complexes, one of formula CgHioFe(CO)3 which was presumed to be the normal diene complex expected from (XXXVII). 

A-lsopropylpyridine-imine Co(I) complexes were efficient catalysts to promote the intermolecular [4+2+2] cycloaddition, which combines two alkynes with butadiene to generate cyclooctatrienes in a highly regioselective manner. The addition of iron powder was found to reduce by-product formation and increase the yield... 

A sequence of nucleophilic additions can be performed in cationic (ri -cycloocta-tetraene)(ti -cyclopentadienyl)iron complexes. The first nucleophile adds anti to the Cp-iron fragment to provide an (Tl -cyclooctatrienyl)-Cp-iron complex. This species can be protonated forming a cationic (T -cyclooctatriene)-Cp-iron complex that in turn can be reacted with a second nucleophile. After protonation and demetalation, cis-5,1-disubstituted cycloocta-1,3-dienes are obtained (Scheme 4-182). 

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