Cyclopentadienyltitanium trichloride

Cyclopentadienyltitanium Compounds with Other Carbon Titanium Links. Cyclopentadienyltitanium trichloride and, particularly, CpgTiClg react with RLi or with RAl compounds to form one or more R—Ti bonds. As noted, the Cp groups stabilize the Ti—R bond considerably against thermal decomposition, although the sensitivity to air and moisture remains. Depending on the temperature, mole ratio, and stmcture of R, reduction of Ti(IV) may be a serious side reaction, which often has preparative value for Cp Ti(Ill) compounds (268,274,275). 

Titanocene dichloride has been built onto a polystyrene support by first introducing cyclopentadienyl methyl groups into the polymer and then reacting these with cyclopentadienyltitanium trichloride (36) ... 

It was found that substituted cyclopentadienyltitanium trichloride, in a combination with methylaluminoxane, exhibited higher catalytic activity for syndiospecific polymerisation of styrene than CpTiCl3 [52,53]. The efficiency of half-sandwich titanocenes as methylaluminoxane-activated precatalysts for the syndiospecific polymerisation of styrene increases in the following order CpTi(OMe)3 < Me4(Me3Si)CpTi(OMe)3 < Cp Ti(OMe)3. Thus, electron-donating substituents on the cyclopentadienyl ligand lead to increased catalyst activity and stability, stereospecificity and polymer Mw. 

An important development is the use of D-glucose-derived alkoxy ligands on titanium in cyciopentadi-enyldi(alkoxy)titanium enolates, which undergo efficient enantioselective aldol reactions with aldehydes. The chiral titanium reagent (30), prepared from reaction of cyclopentadienyltitanium trichloride with two equivalents of (l,2 5,6)-di-0-isopropylidene-a-D-glucofuranose, can be used to transmetal late the lithium enolate of t-butyl acetate in ether solution (equation 10). The titanium enolate generated is then... 

Diazenido complexes were isolated as products from the reaction of trimethylsilylphenyldiazene, Me3Si—N=N—Ph (instead of BSD), with cyclopentadienyltitanium trichloride (CpTiCl3) (74), or pentacarbonyl-manganese bromide [(CO)sMnBr] (75) [Eqs. (94) and (95)]. 

In diethyl ether, BSD reacts with cyclopentadienyltitanium trichloride, CpTiCl3, at — 78°C and with cyclopentadienylvanadium trichloride,... 

A suspension of 11 g (50 mmol) of freshly sublimed cyclopentadienyltitanium trichloride in 400 mL of Ft.O (distilled over Va/benzophcnone) is treated with 23.2 g (50 mmol) of (/ ,/ )-4.5-bis[hydroxy(diphenyl)mcthyl]-2.2-dimethyl-1.3-dioxoIane under argon. After 2 min at r.t., a solution of 12.65 g (110 mmol) of Et5N in 125 mL of Et,0 is added dropwise to the very efficiently stirred mixture over 1 h. Stirring is continued for 12 h. The precipitated Ei, N HC1 (13.8 g) is filtered off under argon and washed three times with 50-mL portions of Ft20. This stock solution (610 mL) is assumed to be 82 mM and can be directly used for further applications. The complex can be isolated by concentration of the stock solution to ca. 75 mL and addition of 300 mL of hexane. After stirring for 30 min. the suspension is fdtered and the residue washed three times with 10-ml. portions of hexane yield 26.8 g (87%) of the pure product. 

Cyclopentadienyllithium, 239 Cyclopentadienyltitanium trichloride, 374 Cyclopentane annelation, 190, 211-212 Cyclopentenones, 24, 253, 278 Cyclopentylidenetriphenylphosphorane, 183... 

Qian, X. Huang, J. Qian, Y. Wang, C. Syndiotactic polymerization of styrene catalyzed by aUcenyl-substituted cyclopentadienyltitanium trichlorides. Appl. Organomet. Chem. 2003, 17, 277-281. 

Cyclopentadienyltitanium trichloride associated with amalgams or alkali metals dimerizes ethylene to 1-butene [93]. 

Some organotin ethers of carbohydrate derivatives have been synthesised as potential pestiddes and the selected acylation of some cyclic dibutylstannylene compounds is discussed in Chapter 7. Treatment of cyclopentadienyltitanium trichloride with l,2 5,6-di-0-isopropylidene-a-D-glucofuranose affords adduct (26) which may be transformed into the chiral organometallic reagents (27)-(29). These react with aldehydes (RCHO) to give products (30)-(32), respectively, with high stereoselectivity. ... 

Gomproportionation. Bis (cyclopentadienyl) titanium dichloride heated 24 hrs. with excess TiGl4 in p-xylene at 115-120° cyclopentadienyltitanium trichloride. Y 84%. Also reconversion s. R. D. Gorsich, Am. Soc. 80, 4744 (1958). 

Solubility in Nonpolar Solvents. Table I lists the solubilities of complexes 1-5 in cyclohexane and perfluoromethylcyclohexane. The ionic complexes 1, 2, and 4 exhibited solubilities of 0.5, 1.5, and 2.5 g/100 mL in cyclohexane, while in the less polar perfluoromethylcyclohexane these values were 0, 0.03, and 0.06 g/100 mL, respectively. The molecular complexes 3 and 5 were far more soluble than the ionic complexes, as exemplified by their solubilities of 4.9 and >22 g/lOOmL in cyclohexane and 0.70 and 1.5 g/100 mL in perfluoromethylcyclohexane, respectively. For comparison, 1,3-bis-(trimethylsilyl)cyclopentadienyltitanium trichloride possessed solubilities of 3.7 100 mL in cyclohexane and 0.62 g/100 mL in perfluoromethylcyclohexane. Addition of a third trimethylsilyl group leads to a significant increase in solubility, although the diketonate substituents also clearly play a role in solubility enhancement. 

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