United States Patent (19) Ill) Patent Number: 5,004,820 Buchwald Et Al

United States Patent (19) Ill) Patent Number: 5,004,820 Buchwald et al. 45) Date of Patent: Apr. 2, 1991 54) PREPARATION OF CHIRAL 0277004 8/1988 European Pat. Off. .............. 556/53 METAL LOCENE DIHALIDES 0284707 10/1988 European Pat. Off. .............. 556/53 0284708 10/1988 European Pat. Off. .............. 556/53 (75) Inventors: Stephen L. Buchwald; Robert B. Grossman, both of Somerville, Mass. OTHER PUBLICATIONS 73) Assignee: Massachusetts Institute of Wild et al., J. Organomet. Chem. 232 (1982) 233-47, Technology, Cambridge, Mass. Synthesis and Molecular Structures of Chiral an sa-Titanocene Derivatives with Bridged Tetrahy (21) Appl. No.: 390,062 droindenyl Ligands. 22 Filed: Aug. 7, 1989 Schafer et al., J. Organomet. Chem. 328 (1987) 87-99, Diastereomeric Derivatisation and Enantiometer Sepa (51) Int. C. ............................................. CO7F 00/00 ration of Ethylenebis (Tetrahydroindenyl)--Titanium (52) U.S. C. ...................................................... 556/53 Field of Search .......................................... 556/53 and -Zirconium Dichlorides. (58) Ewen et al., J. Am. Chem. Soc. 109 (1987) 6544, Crystal 56) References Cited Structures and Stereospecific Propylene Polymeriza U.S. PATENT DOCUMENTS tions with Chiral Hafnium Metallocene Catalysts. 4,169,845 10/1979 Jonas ................................. 556/53 X Collins et al., J. Organomet. Chem. 342 (1988) 21, 4,310,648 1/1982 Shipley et al. ...................... 526/14 X-Ray Structures of Ethylenebis (Tetrahydroindenyl 4,361,685 11/1982 Shipley ........... ...... S26/14 )-Titanium and -Zirconium Dichlorides: A Revision. 4,404,344 9/1983 Sinn et al. ........................... 526/160 4,522,982 6/1985 Ewen .................................. 525/240 Primary Examiner-Paul F. Shaver 4,530,914 7/1985 Ewen et al. ......................... 502/13 Attorney, Agent, or Firm-Thomas J. Engellenner 4,701,432 0/1987 Welborn, Jr. ....................... 502/13 4,752,597 6/1988 Turner ........... ... 502/104 57 ABSTRACT 4,874,880 10/1989 Niya et al. ............................ 556/53 A process for preparing chiral metallocene dihalides as 4,892,851 1/1990 Ewen et al. ....... ... 556/53 X catalytic agents in improved yields by deprotonation of 4,910,121 3/1990 Riediker et al., .................. 556/53 X 1,2-bis(2,3-disubstituted cyclopentadienyl)ethane foll FOREIGN PATENT DOCUMENTS lowed by condensation with hafnium tetrachloride or 0035242 9/1981 European Pat. Off. .............. 556/53 zirconium tetrachloride. 0279153 8/1985 European Pat. Off. ...... 556/53 0277003 8/1988 European Pat. Off. .............. 556/53 3 Claims, No Drawings 5,004,820 1. 2 Exemplary alkylene radicals are methylene, ethylene, PREPARATION OF CHRAL METALLOCENE propylene, butadienylene and the like. Exemplary halo DHALDES gen atoms include chlorine, bromine, and iodine. The Government has rights in this invention pursuant DETAILED DESCRIPTION to grant Number GM34917-05 awarded by the National The process of this invention comprises deprotonat Institutes of Health. ing a compound of Formula I with two equivalents of potassium hydride followed by condensation with a BACKGROUND OF THE INVENTION Group 4 metal halide to yield a chiral metallocene di This invention relates to an improved process for O halide as illustrated in the following reaction Scheme: preparing chiral metallocene dihalides. Chiral metallocene dihalides and derivatives are widely used as catalytic components in cocatalyzed polymerization reactions. In particular, transition met R R KH G al-containing metallocene compounds are useful in con 5 MX.2THF junction with alumoxane cocatalysts in the polymeriza O tion of ethylene and the copolymerization of ethylene R R2 MX4 with 1-olefins or diolefins. Such catalyst systems are also useful in the production of isotactic polypropylene and other poly olefins. Chiral metallocene dihalides such as ethylenebis(m- indenyl)hafnium dichloride and ethylenebis(m- indenyl)zirconium dichloride have been prepared by methods disclosed in Ewen et al., J. Am. Chem. Soc. MX 1.09: 6544 (1987) and Collins et al., J. Organomet. Chem. 25 342: 21 (1988), respectively, e.g., the deprotonation of 1,2-bis(3-indenyl)ethane with two equivalents of n butyllithium followed by condensation with hafnium tetrachloride or zirconium tetrachloride. Although I these prior art processes operate successfully, the yields 30 are not optimum. R2 The process of this invention results in higher yields Wherein R, R2, and M are as defined above. than the prior processes. Potassium hydride is suspended in an organic solvent SUMMARY OF THE INVENTION such as tetrahydrofuran. Compound I is dissolved in an 35 Chiral metallocene dihalides are produced by a new equivalent amount of organic solvent such as tetrahy route from 1,2-bis(2,3-disubstituted cyclopentadienyl)e- drofuran and added to the potassium hydride suspen thane by deprotonation with potassium hydride fol sion with evolution of hydrogen. MX or its bis(tetrahy lowed by condensation with a Group 4 metal halide. drofuran) adduct is also dissolved in an organic solvent This invention provides a process for preparing, in such as tetrahydrofuran. Both solutions are added to a improved yields, a chiral metallocene dihalide repre 40 common organic solvent such as tetrahydrofuran, re sulting in the formation of Compound II. sented by the formula: When Compound II is an ethylenebis-(n-indenyl)- metal dihalide compound, it can be converted to an R2 I octahydro species, particularly useful for the produc 45 tion of isotactic polypropylene, by suspending Com pound II in a hydrogenator in the presence of a plati num dioxide catalyst and an organic solvent such as methylene chloride. The hydrogenator is pressurized to MX2 about 1,000 psi hydrogen and left to stir for about eight 50 hours. The resulting solution is diluted with a sufficient amount of methylene chloride and filtered. The filtrate is evaporated, leaving behind a solid material. The following non-limiting examples further illus trate the invention: 55 EXAMPLE 1. wherein both R and R2, which can be the same or different, represent hydrocarbyl radicals such as alkyl, Ethylenebis(m-indenyl)zirconium dichloride alkenyl, aryl, alkylaryl, or arylalkyl radicals having 688 mg (17.2 mmol) potassium hydride was sus from 1 to 20 carbon atoms, and R2 also represents hy pended in 20 ml of tetrahydrofuran. 2.01 g (7.78 mmol) drogen, or R1 and R2 are joined together with the two ,2-bis(3-indenyl)ethane was dissolved in 20 ml tetrahy carbon atoms of the cyclopentadienyl ring form a drofuran and was added by cannula to the potassium C4-C6 ring; X is a halogen such as chlorine, bromine hydride, resulting in an orange solution and white sus and iodine, and M represents zirconium or hafnium pension changing to a green solution with large (except M is not zirconium when X is bromine). 65 amounts of evolved hydrogen. 2.94 g (7.74 mmol) zirco Exemplary hydrocarbyl radicals are methyl, ethyl, nium tetrachloride bis(tetrahydrofuran) adduct was propyl, butyl, amy 1, isoamyl, hexyl, isobutyl, octyl, dissolved in 45 ml tetrahydrofuran resulting in a color nonyl, decyl, cetyl, 2-ethylhexyl, phenyl, and the like. less solution. The two solutions were added slowly and 5,004,820 3 . .. 4 simultaneously to 50 ml tetrahydrofuran. The addition added drop-wise simultaneously with 4.56 g (19.4 of the two solutions was completed after about an hour mmol) zirconium tetrachloride bis(tetrahydrofuran) and a half. Anhydrous hydrogen chloride was bubbled adduct in 125 ml tetrahydrofuran to 100 ml tetrahydro through the solution, and then the solution was evapo furan at rogm temperature. The addition was complete rated. The reaction mixture was then washed copiously after about two hours. Gaseous hydrogen chloride was with ether, followed by 5 ml of 4M hydrochloric acid bubbled through the solution until a color change (dark chloride, 5 ml water, 5 ml ethanol, 5 ml ethanol, 5 ml red-brown to yellow) was complete. The Solution was ether, and 5 ml ether to give a yellow-orange powder. evaporated. 5.95g of solid was collected on a filter flask The resultant amount of product ethylenebis(m- after diluting the yellow oily solid with ether. This indenyl)zirconium dichloride was 2.464 g (5.89 mmol), 10 material was washed with 10 ml of 4M hydrochloric 76% yield. acid, 10 ml water, 10 ml ethanol, 10 ml ethanol, 10 ml EXAMPLE 2 ether, and 10 ml ether to give 1.908 g (4.5 mmol), 24% Ethylenebis(m-tetrahydroindenyl)-hafnium dichloride yield of ethylenebis(m-indenyl) zirconium dichloride as 15 a powdery yellow solid. The resultant compound was 2.00 g (7.74 mmol) 1,2-bis(3-indenyl)ethane in 25 ml identified by NMR. The yield was significantly less than tetrahydrofuran was added to 688 mg (17.2 mmol) po that for the same compound in Example 1 of the present tassium hydride in 25 ml tetrahydrofuran. Also, 2.48 g invention reported above. (7.74 mmol) hafnium tetrachloride was dissolved in 100 ml tetrahydrofuran. An additional 50 ml of tetrahydro We claim: furan was added to the 1,2-bis(3-indenyl)ethane and 20 1. A process for preparing a chiral metallocene dihal potassium hydride solution. The two solutions were ide compound added drop-wise to 100 ml of tetrahydrofuran at room comprising reacting a compound represented by the temperature. The addition was complete after 1.5 hours. formula: Gaseous hydrogen chloride was bubbled through the yellow solution. The solution was stripped down to 25 give a brown-yellow oil. The oil was taken up in ether and filtered to give a yellow-white powder of ethylenebis(mis-indenyl)hafnium dichloride confirmed by NMR. The yellow-white powder was washed with two portions of 5 ml water, 2 portions of 5 ml ethanol, R2 R2 5 and 10 ml portions of ether and then was dried with suction to give 1.501 g (3.02 mmol), 39% yield of wherein both R1 and R2, which can be the same or ethylenebis(m-indenyl)hafnium dichloride.

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