Titanocene dichloride, and

Though the usual product of epoxide reductions is the alcohol (10-85), epoxides are reduced all the way to the alkane by titanocene dichloride and Et3SiH-BH3. ... 

In 1985, Eisch et al. isolated a cationic alkenyltitanium complex (55) by the insertion of an alkyne into the cationic Ti-C bond generated from titanocene dichloride and methylaluminum dichloride (Eq. 2) [77], Similarly, a mixture of Cp2TiCl(CH2SiMe3) and A1C13 afforded the solvent-separated ion pairs,... 

Aluminum-free titanocene-methylidene can be generated by thermolysis of titana-cyclobutanes 6, which are prepared by reaction of the Tebbe reagent with appropriate olefins in the presence of pyridine bases [9]. Alternatively, the titanacyclobutanes are accessible from titanocene dichloride and bis-Grignard reagents [10] or from 71-allyl titanocene precursors [11]. The a-elimination of methane from dimethyltitanocene 7 provides a convenient means of preparing titanocene-methylidene under almost neutral conditions [12] (Scheme 14.5). 

Methylenative dimerization takes place when terminal alkynes are treated with the tita-nocene/methylidene/zinc halide complex generated from titanocene dichloride and CH2(ZnI)2. The process is believed to involve the formation of a titanacyclobutene intermediate [75],... 

Other metal complexes also have promising anticancer activity. Two Ti(IV) complexes are on clinical trial, an acetylacetonate derivative (budotitane) and titanocene dichloride, and the antimetastic activity of octahedral Ru(III) complexes is attracting attention, one of which is now on clinical trial. Ru(III), like several other metal ions, can be delivered to cells via the iron transport protein transferrin. 

The antitumor activity of titanocene dichloride 21 was first recognized in 1979 (150), and since then the activity of several other metallocenes (V, Nb, Mo, Fe, Ge, and Sn) has been reported (151). Most interest has centered on titanocene dichloride and on vanadocene dichloride 22, which are active against a diverse range of human carcinomas, including gastrointestinal and breast carcinomas, but not against head and neck cancers. There appears to be a lack of crossresistance between titanocene dichloride and cisplatin. 

After formation of complex by combination of the titanocene dichloride and trialkyl aluminum, alkylation of the titanium component is presumed to take place. 

Mokdsi G, Harding MM (1998) Water soluble, hydrolytically stable derivatives of the antitumor drug titanocene dichloride and binding studies with nucleotides. J Organomet Chem 565 29-35... 

Carbotitanation of alkyuylsilanes, The reaction of an alkynylsilane with 1 equiv. each of titanocene dichloride and dimethylaluminum chloride followed by hydrolysis with aqueous sodium bicarbonate or sodium hydroxide results mainly in c -carbometalation (equation I). Addition of triethylamine prior to quenching results in loss of stereochemistry. Use of trimethylaluminum results in similar CM-addition, but this reaction is slower than that with (CH3)2A1C1. Surprisingly, alkynylsilanes do not react with zirconocene dichloride and dimethylaluminum chloride. 

With transition metals the lability of their carbon-metal bonds often does not permit the isolation of the metal alkyl. Feasible preparation then requires the presence of stabilized ligands on the metal, such as phosphines, 2,2-bipyridyl and cyclopentadienyl. The preparation of dimethyltitanocene from titanocene dichloride and MesAI is illustrative." A compilation of typical preparations is provided in Table 6. 

Acidic hydrolysis afforded the titanocene dichloride and the corresponding l,3,4-triaryl-2-aroylcyclopentadienyl 70 or, in some cases, its dehydrated product. 

Biphenyl-bridged bis-Cp titanocene dichloride and dimethyl complexes have been synthesized, and the kinetic resolution of the racemic final mixture of the products has been carried out. A mixture of diastereomers is obtained by treatment of the dimethyl compound with O-acetyl-mandelic acid, while enantiomerically pure products result in the reaction of the dichloro derivative with (i )-binaphthol and 1 equiv. of LiBun (Scheme 661).1050... 

The reaction between titanocene dichloride and salts of diacids were studied.181,183 The reactive species in both the aqueous solution and IF systems are believed to be R-C002 and Cp2Ti+2 with reaction occurring within the aqueous layer.181,183 The condensation of titanocene dichloride with disodium terephthalate in the IF systems occurs via a pseudo-first-order reaction R = k[Cp2TiCl2]... 

M. Williams, C. Carraher, F. Medina, M. Aloi, Comparative Raman and Infrared Vibrational Study of the Polymer Derived from Titanocene Dichloride and Squaric Acid, in Structure-Property Relations in Polymers, M. Urban, C. Craver, Eds., p. 769-776, American Chemical Society, Washington, DC, 1993. 

The investigations concerning the mode of action of the metallocene dihalides represented by titanocene dichloride and vanadocene dichloride are based on four experimental pillars ... 

Microanalytical Studies. The EELS investigations after in vivo as well as after in vitro treatment of EAT with the antitumor agents titanocene dichloride and vanadocene dichloride reveal reproducibly the main enrichment of the central metals Ti and V within the nuclear heterochromatin. To a minor extent, the metals are associated with the euchromatin, the nucleolus, and the cytoplasmic ribosomes. In most cases, no metal atoms can be detected in other cellular regions by EELS. This means that the treatment with titanocene or vanadocene dichloride results apparently in an accumulation of the central metals Ti and V within those cellular regions which are rich in nucleic acids. 

Titanocene dichloride, methyl magnesium chloride, DMT, and the dimer decomposition product of DMT are all visible by mid-IR. The absorbances for titanocene dichloride and DMT overlap, and monomethylmonochloro titanocene, a transient intermediate observed by NMR and normal-phase HPLC, was initially not detected by mid-IR but was assumed to have similar absorbance. 

An irreversible tt-ct rearrangement of cyclopentadienyl ligands has been observed in the reaction of titanocene dichloride and dimethyl sulfoxide (DMSO) 15). 

Recently, the unusual behavior of reaction systems that involve titanocene toward the normally quite inert molecule N2 has been the subject of considerable interest. The fixation and reduction of molecular nitrogen has been observed in mixtures of titanocene dichloride and ethyl magnesium bromide and in other systems containing titanocene derivatives (100-108). 

Petasis and co-worker reported that methylenation of selenol and thio esters with dimethyl titanocene led to the formation of the corresponding vinyl se-lenides and sulfides (Eq. 58) [111]. Dimethyl titanocene can be easily prepared from titanocene dichloride and methyllithium [112]. The methylenation reactions involve simply heating a mixture of dimethyl titanocene and chalcogeno esters at 60-75 °C. 

The infrared spectra of titanocene dichloride and the squarate polymer (Cp2Ti (C O )) are shown in Figure 1 and the Raman spectrum of (Cp2Ti (C O ) is shown in Figure 2. 

Cuerva et developed an effleient propargylation of aldehydes and ketones using propargylic carbonates as pronucleophiles at room temperature in the presence of titanocene dichloride and palladium dichloride as catalyst system obtaining good yields and excellent regioselectivity. Oltra and... 

In comparison, F MALDI data obtained from the high-range instrument is shown in Table 13.10 for the product of titanocene dichloride and acyclovir (1). No loss of the cyclopentadiene groups occurs. 

---