Pentafulvene Complexes

Hayashi, T. Mise, M. Fukushima, M. Kagotani, N. Nagashima, Y. Hamada, A. Matsumoto, S. Kawakami, M. Konishi, K. Yamamoto, and M. Kumada, Bull. Chem. Soc.Jpn., 1980,53, 1138. 

Other more specific reviews are included at the beginning of the appropriate section. 

The reduction of arenes and the roles of solvents in catalytic hydrogenation have been briefly reviewed. 

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Scherer A, Kollak K, Liitzen A, et al. Low-valent titanium—pentafulvene complexes— formation of dinuclear titanium-nitrogen complexes. Eur J Inotg Chem. 2005 2005 1003-1010. 

Photoreactions of [Cr(CO)3( /6-C7H8)] (41) with 6-mono- and 6,6-disub-stituted pentafulvenes (59a-59f) preferentially yield dicarbonyl complexes with substituted tj3 5-2-cyloheptadienylene-2-cyclopentadienylidenemethane chelate ligands (82,83). In the course of the reaction, C-6 of the fulvene forms a C—C bond to C-l of the 1,3,5-cycloheptatriene ligand, and one CO ligand is displaced. This reaction is of the same type as the formation of the f/3 5-[ 1 -(3-butene-1,2-diyl)-7-isopropylidenecycloheptadienyl] complexes 47c, 47e and 47t. The fulvene unit is transformed into a monosubstituted cyclo-pentadienyl entity, / -coordinated to the chromium, with the 1,3,5-cyclo-... 

Fulvene Complexes.—Several ( -fulvene)Cr(CO)3 complexes have been obtained by photochemical ligand-exchange reactions of benchrotrenes with 6,6-disubsti-tuted pentafulvenes. The crystal structure and C n.m.r. spectrum of the 6-(dimethylamino) complex have shown that it is best formulated as a... 

In 2001, Barluenga and coworkers [43] developed the [6+3] cycloaddition of chromium alkenyl carbene complexes 189 with pentafulvenes 15, involving nucleophilic 1,2-addition and the subsequent cyclization prompted by [l,2]-M(CO)5 shift, to afford a number of indenes 190 and indanones 193 (Scheme 7.43). 

Later, in 2005, the group reported the [6+3] cycloaddition of Fischer aminocar-bene complexes 194 to pentafulvenes 47 by the l,2-addition/[l,2]-M(CO)5 shift mechanistic model affording aminoindene derivatives 196 (Scheme 7.44) [44]. 

Although pentafulvenes are the by far most common fulvenes, there are some publications describing the synthesis of heptafulvene complexes. The reaction of (cycloheptatrienyl-7-methyl) phenylsulfonate (92) with sodium [cyclopentadi-enyldicarbonylferrate(II)] afforded complex 93 in 45% yield, from which hydride was abstracted quantitatively by treatment with triphenylcarbenium ions. The heptafulvene complex formed was described by resonance formulas 94 and 95, the latter with an intact aromatic cycloheptatrienylium substructure (Scheme 10.32) [84, 85]. 

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