Dichlorobis zirconium

Zirconocene dichloride Zirconium, dichloro-jc-cyclopentadienyl- (8)- Zirconium, dichlorobis(r 5-2,4-cyclopentadien-1-yl)- (9) (1291-32-3)... 

In a similar manner to that described for bicyclic lactams (Section 1.1.1.3.3.4.1.5.I.). alkylation reactions of tricyclic lactams, which contain a fused benzene ring adjacent to the carbon undergoing alkylation, have been exploited14. The first alkylation of the benzo-annulated bicyclic lactam 1 gives a mixture of diastereomers, which is then further alkylated. In the second alkylation step, the counterion on the alkoxide, which is formed prior to enolate formation, proved to be crucial for the diastereoselectivity of the subsequent alkylation reaction. The best diastcrcoselectivity was obtained when either dichlorobis(ij5-cyclopentadienyl)zirconium or triisopropoxytitanium chloride was added to the preformed alkoxide, followed by enolization and alkylation. Using this method the second alkylation step gives a satisfactory diastereoselectivity. Hydride reduction of the purified major diastereomer 2, followed by acid treatment of the product, furnishes chiral naphthalenones 414. 

ALDOL CONDENSATION Cesium fluoride. Dialkylboron trifluoromethane-sulfonates. Dichlorobis(cyclopentadi-enyl)zirconium. Diisobutylaluminum phenoxide. 2,5-Dimethylphenylpropi-onate. DimetIiyl(phenyllhio)aIuminum. Lithium iodide. Triethylborane. Tri-methylsilyl trifluoromethanesulfonate. Triphenyltin chloride. TrisCdiethyI-amino)sulfonium difluorotrimethyl-siliconate. 

HYDRO ALUM [NATION Dichlorobis-(cyclopcntadienyl)titanium. Dichloro-his(cyclopentadicnyl)zirconium. Lithium aluminum hydride-I)ichlorobis(cyclo-pentadienyi)zirconium. Borane-Di-metliyl sulfide. 

HOMOALLYLIC ALCOHOLS Allyltin dilluoroiodide. Dichlorobis(cycIo-penta-dienyl)titanium. Ethylaluminum dichloride. Stannous fluoride. Trimethyl-aluminum-Dichlorobisfcyclopenta-dicnyl)zirconium. 

Several other chiral catalysts have also been tested, but they have been less satisfactory. Specifically, the reaction of 1 -octene with Me3Al in the presence of 8 mol % of dichlorobis(l-neoisomenthylindenyl)zirconium, dichlorobis(l-neoisomenthyl-4,5,6,7-tetrahydroindenyl)zir-conium, (( ,R)-dichloroethylencbis(4,5,6,7-tetrahydro-l-indenyl)zirconium, and (R,R) ... 

HYDROZIRCONATION Dichlorobis(cyclo-pentadicnyl)zirconium-r-Butylmagnesium bromide. 

Dichlorobis(cyclopentadienyl)zirconium -Butylmagnesium chloride, Cl2ZrCp2-(CH3)3CMgCl. 

Anti diastereoselectivity gives the optically active (S)-p-hydroxy ester while syn diastereoselectivity leads to the (/ )-P-hydroxy ester, via a chelated six-membered transition state (eq 3). Since the anti intermediate is more stable, the (S)-P-hydroxy ester predominates under thermodynamic conditions (Table 1, entry 1). Higher diastereoselectivity is achieved by changing the counterion from lithium to a more chelating one such as zinc (Table 1, entry 2). On the other hand, in order to obtain diastereoselection under kinetic control, zirconium enolates (prepared by treating the lithium enolate with Dichlorobis(cyclopentadienyl)zirconium) are used, leading to the (/ )-p-hydroxy ester (Table 1, entry 3) in high yield. 

Dichlorobis(2,4-pentanedionato)titanium(IV), synthesis 10 Tris(2,4-pentanedionato)zirconium(IV) chloride, synthesis 11 Phenyllead(lV) azides (includes triphenyllead chloride and diphenyllead dichloride), synthesis 15 Diphenyl phosphorochloridite, synthesis 17 Mercapto derivatives of chlorocyclophosphazenes, synthesis 21 (Trichlorophosphoranylidene)amidophosphoryl dichloride, synthesis 22... 

The. reaction of various monosubstituted alkenes containing hydrocarbon substituents, as well as those containing heteroatom substituents, with Me3Al and a catalytic amount of a chiral dichlorobis(l-neomenthylindenyl)zirconium derivative provides, after oxidation with O7, 2-methylalkan-l-ols in high yields with up to 85% ee [126] (Scheme 7-106). 

HYDROALUMINATION Dichlorobis-(cyclopentadienyl)titanium. Dichloro-bis(cyclopentadienyl)zirconium . Lithium aluminum hydride-Dichlorobis(cyclo-pentadienyl)zirconium. Borane-Di-methyl sulfide. 

Lithium aluminum hydride-Dichlorobis-(cyclopenta-dienyl)zirconium, 237-... 

Dichlorobis(cyclopentadienyl)zirconium, (CsH5)2ZrCl2 (1). Mol. wt. 292.32. Supplier Alla. 

Lithium aluminum hydride-Dichlorobis(cyclopcntadienyl)zirconium. 

The analogous compound 29, derived from 3,3-diphenylcyclopropene, is formed in far better yield (86%) in the reaction of dichlorobis(t/ -cyclopentadienyl)zirconium with the cyclopropene and butyllithium. ... 

A 1.6 M solution of BuLi in hexane (7.31 mL, 11.4 mmol) was slowly added to a solution of dichlorobis(j -cyclopentadienyl)zirconium (1.67 g, 5.7 mmol) in THE (25 mL) at — 78 C. The mixture was then stirred for an additional 1 h at — 78 C. Then, 3,3-diphenylcyclopropene (2.31 g, 11.4 mmol) was added and the mixture was warmed to 20 C and stirred at this temperature for 2 h. All volatiles were then removed in vacuo and a toluene solution of the residue was filtered through Cclite and again evaporated to drymess in vacuo. After rccrystallization of the residue from EtjO (40 mL), yellow crystals were obtained yield 2.97 g (86%) mp 121 C (dec.),... 

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