WO1997042158A1

WO1997042158A1 - Synthesis of a substituted cyclopentadiene compound

Info

Publication number: WO1997042158A1
Application number: PCT/NL1997/000197
Authority: WO
Inventors: Gerardus Johannes Maria Gruter; Johannes Antonius Maria Van Beek
Original assignee: Dsm N.V.
Priority date: 1996-05-03
Filing date: 1997-04-16
Publication date: 1997-11-13
Also published as: AU2310997A; NL1003009C2

Abstract

Process for substituting a cyclopentadiene with at least 1 group of the form -RDR'n by deprotonating cyclopentadiene already substituted with at least one other group through reaction with a base, sodium or potassium and then reacting the cyclopentadienyl anion formed with a compound containing a sulphonyl group, the sulphonyl-group-containing compound being a compound according to the formula (R'nD-R-Sul), wherein R is a linking group, R' is a substituent, D is a heteroatom from group 15 or 16 of the Periodic System of the Elements and Sul is a sulphonyl group.

Description

SYNTHESIS OF A SUBSTITUTED CYCLOPENTADIENE COMPOUND

The invention relates to a process for substituting a cyclopentadiene with at least one group of the form -RDR'_n by deprotonating a cyclopentadiene compound already substituted with at least one other group through reaction with a base, sodium or potassium and then reacting the cyciopentadienyl anion formed with a compound containing a sulphonyl group. Hereinafter, cyclopentadiene will be abbreviated as "Cp". The same abbreviation will be used for a cyciopentadienyl group if it is clear from the context whether cyclopentadiene itself or the anion thereof is meant.

A method for such a synthesis is disclosed by Szymoniak et al. (J. Org. Chem. 1990, 55, 1429 - 1432).

In the latter, a process is described for the synthesis of a tetramethylcyclopentadiene having a diphenylphosphine-containing substituent. The synthesis proceeds in the following manner: the tetramethylcyclo- pentadienyl is deprotonated to form the anion, said anion is reacted with 2-chloroethyl tosylate and then, in a second reaction step, with lithiumdiphenyl phosphide. The yield is 68%. In such an alkylation reaction, a plurality of isomers of the alkylated cyclopentadiene can be obtained.

However, Jutzi et al. (Synthesis 1993, 684) describes why such a synthesis route cannot result in the 1,2, 3,4,5-pentasubstituted cyclopentadiene because only geminal substitution of the tetramethylcyclo- pentadiene occurs. Jutzi isolates these geminal products with a yield of 65%. Geminally substituted cyclopentadiene is a cyclopentadiene containing two substituents which are not identical to a hydrogen atom on the sp³ carbon atom of the cyclopentadiene ring. The object of the invention is to provide a simple method for synthesizing a substituted Cp compound of which at least 1 substituent has the form - RDR'_n, the conversion being as high as possible and as few geminal products as possible being formed. The invention is characterized in that the sulphonyl-group-containing compound is a compound according to the formula (R'_nD-R-Sul) , wherein R is a linking group, R' is a substituent, D is a heteroatom from group 15 or 16 of the Periodic System of the Elements, n is the number of R' groups bound to D and Sul is a sulphonyl group.

Surprisingly, it has now been found that if the introduction of a substituent which has the form - RDR'_n is carried out in the above way, nongeminally substituted Cps can definitely be obtained.

A further advantage of the synthesis process according to the invention is that, in contrast to the process which is carried out by Szymoniak and Jutzi for attaching one or more substituents of the form -RDR'_n to a substituted Cp compound, only one synthesis step needs to be carried out.

Another advantage of the synthesis process according to the invention is that yields greater than or equal to 95% are achieved.

During the method according to the invention geminal product is formed only in part. The geminal products can easily be isolated by converting the product from the above synthesis into a salt by reaction with potassium, sodium or a base, after which said salt is washed with a dispersant in which the salt of the nongeminal products hardly dissolves.

The substituted Cp compound can be used as ligand in a metal complex.

Cp compounds are understood as meaning Cp itself and substituted Cp, in which case two substituents may form a closed ring.

A substituted Cp compound contains at least 1 alkyl, alkenyl and/or aralkyl substituent.

The alkyl substituents may be linear, branched or cyclic alkyl groups. In addition to carbon and hydrogen, one or more heteroatoms from the groups 14 - 17 of the Periodic System, for example 0, N, Si or F, may also occur in the substituents. Examples of suitable substituents are methyl, ethyl, (iso)propyl, secondary butyl, secondary pentyl, secondary hexyl and secondary octyl, (tertiary) butyl and higher homologs, cyclohexyl, benzyl. Combinations of these substituents on the Cp compound are also possible.

For the Periodic System, see the new IUPAC notation to be found on the inside of the cover of the Handbook of Chemistry and Physics, 70th edition, 1989/1990.

Substituted Cp compounds can, for instance, be prepared by reacting a halide of the substituting compound in a mixture of the Cp compound and an aqueous solution of a base in the presence of a phase-transfer catalyst. A virtually equivalent amount with respect to the Cp-compound of the halogenated substituting compound can be employed. An equivalent amount is understood as meaning an amount in moles which corre¬ sponds to the desired substitution level, for example 2 mol per mol of Cp compound if disubstitution with the respective substituent is intended.

Depending on the size and the steric hindrance associated therewith of the substituting compounds, trisubstituted to hexasubstituted Cp compounds can be obtained. If reaction is carried out with a tertiary halide of a substituting compound, only trisubstituted Cp compounds can as a rule be obtained, but with primary and secondary halide of a substituting compound, tetrasubstitution and usually even penta- substitution or hexasubstitution can generally be achieved. Because a substitute of the form -RDR'_n is additionally introduced in a second step by means of the process according to the invention, four substituents are introduced in said first step as a maximum.

The substituents are preferably used in the process in the form of their halides.

With this process, it is also possible, without intermediate separation or purification, to obtain Cp compounds which are substituted with specific combinations of substituents. Thus, for example, a disubstitution may first be carried out with the aid of a certain halide of a substituting compound and, in the same reaction mixture, a third substitution can be carried out with another substituting compound by adding a second, different halide of a substituting compound to the mixture after a certain time. This can be repeated, so that it is also possible to prepare Cp derivatives containing three or more different substituents.

The substitution takes place in a mixture of the Cp compound and an aqueous solution of a base. The concentration of the base in the solution is between 20 and 80w%. Hydroxides of an alkali metal, for example K or Na, are very suitable as a base. The base is present in an amount of 5 - 60 mol per mol of Cp compound.

The substitution takes place in the presence of a phase-transfer catalyst which is capable of trans¬ ferring OH ions from the aqueous phase to the, Cp-con- taining and halide-containing, organic phase which react therein with an H atom which can be cleaved from the Cp compound. The phase-transfer catalysts are used in an amount of 0.01 - 2 equivalents with respect to the amount of Cp-compound.

In carrying out the method, the components can be added to the reactor in various sequences. After the completion of the reaction, the aqueous phase and the organic phase containing Cp compound are separated. The Cp compound is then extracted from the organic phase by fractional distillation. During the first step of the synthesis route, a Cp compound already substituted with at least one other group is deprotonated by reaction with a base, sodium or potassium. As base, use may be made, for example, of organolithium compounds (R³Li) or organomagnesium compounds (R³MgX), where R³ = an alkyl, aryl or aralkyl group and X = halide, such as, for example, n-butyllithium or isopropylmagnesium chloride. Potassium hydride, sodium hydride, inorganic bases, such as NaOH and KOH, and alcoholates and amides of Li, K and Na can also be used as base. Mixtures of the abovementioned compounds can also be used.

Said reaction can be carried out in a polar dispersant, such as, for example, an ether. Examples of ethers are tetrahydrofuran (THF) or dibutyl ether. Nonpolar solvents, such as, for example, toluene can also be used.

The cyciopentadienyl anion formed then reacts, during a second step of the synthesis route, with a compound according to the formula (R'_nD-R-Sul) , wherein

R is a linking group,

R' is a substituent,

D is an electron-donating heteroatom from group 15 or

16 of the Periodic System of the Elements, n is the number of R' groups bound to D and Sul is a sulphonyl group.

The respective components in this compound are dealt with in greater detail below.

a) The RPR '_n group

The R group forms the link between the Cp compound and the DR'_n group. The length of the shortest link between the Cp and D is critical to the extent that, if the Cp compound is used as ligand in a metal complex, it is decisive for the accessibility of the metal by the DR'_n group in order thus to facilitate any intramolecular coordination. An unduly short length of the R group (or bridge) may cause the donor to be unable to coordinate well as a result of ring tension.

The R' groups may each separately be a hydrocarbon radical containing 1 - 20 carbon atoms (such as alkyl, aryl, arylalkyl and the like). Examples of such hydrocarbon radicals are methyl, ethyl, propyl, butyl, hexyl, decyl, phenyl, benzyl and p-tolyl. R' may also be a substituent which contains one or more heteroatoms from group 14 - 16 of the Periodic System of the Elements in addition to or instead of carbon and/or hydrogen. Thus, a substituent may be a group containing N, 0 and/or Si.

The R group may be a hydrocarbon group containing 1 - 20 carbon atoms (such as alkylidene, arylidene, arylalkylidene and the like). Examples of such groups are methylene, ethylene, propylene, butylene, phenylene, optionally having a substituted side chain. Preferably, the R group has the following structure: (-ER² ₂-)_p where p = 1 - 4 and E is an atom from group 14 of the Periodic System. The R² groups may each be H or a group as defined for R'.

More preferably the R-group has the structure -CR² ₂-(ER² ₂-)_p_₁ so that the R-group is linked to the Cp-compound with a carbon atom. The main chain of the R group may thus contain silicon or germanium in addition to carbon. Examples of such R groups are: dialkylsilylene, dialkylgermylene, tetraalkyldisilylene or dialkylsilaethylene (-(CH₂) (SiR² ₂)-) .

The alkyl groups (R²) in such a group preferably have 1 - 4 C atoms and are, more preferably, a methyl or ethyl group.

The DR'_n group comprises a heteroatom D chosen from group 15 or 16 of the Periodic System of the Elements and one or more substituent(s) R' bound to D. The number of R' groups (n) is coupled to the nature of the heteroatom D in such a fashion that n = 2 if D originates from group 15 and that n = 1 if D originates from group 16. Preferably, the heteroatom D is chosen from the group comprising nitrogen (N) , oxygen (0), phosphorus (P) or sulphur (S); more preferably, the heteroatom is nitrogen (N) . The R' group is also preferably an alkyl, more preferably an n-alkyl group containing 1 - 20 C atoms. More preferably, the R' group is an n-alkyl containing 1 - 10 C atoms. Another possibility is that two R' groups in the DR'_n group are joined to each other to form a ring-type structure (so that the DR'_n group may be a pyrrolidinyl group). The DR'_n group may bond coordinatively to a metal.

b) The sulphonyl group

The sulphonyl group has the form -0S0₂R⁶, wherein R⁶ is a hydrocarbon radical containing 1 - 20 carbon atoms (such as alkyl, aryl, aralkyl and the like). Examples of such hydrocarbon radicals are butane, pentane, hexane, benzene and naphthalene. R⁶ may also contain one or more heteroatoms from group 14 - 17 of the Periodic System of the Elements, such as N, 0 or F, in addition to or instead of carbon and/or hydrogen. Examples of sulphonyl groups are: phenylmethanesulphonyl , benzenesulphonyl, 1-butanesulphonyl, 2, 5-dichlorobenzenesulphonyl, 5-dimethylamino-l-naphthalenesulphonyl, pentafluoro- benzenesulphonyl, p-toluenesulphonyl, trichloromethane- sulphonyl, trifluoromethanesulphonyl, 2,4,6- triisopropylbenzenesulphonyl, 2,4,6- trimethylbenzenesulphonyl, 2-mesitylenesulphonyl, methanesulphonyl, 4-methoxybenzenesulphonyl, 1- naphthalenesulphonyl, 2-naphthalenesulphonyl , ethane- sulphonyl, 4-fluorobenzenesulphonyl and 1-hexadecane- sulphonyl.

Preferably, the sulphonyl group is p-toluene¬ sulphonyl or trifluoromethanesulphonyl.

The second reaction step can be carried out in a polar dispersant, such as, for example, an ether. Examples of ethers are THF or dibutyl ether. Nonpolar solvents, such as, for example, toluene, can also be used.

The temperature at which the reaction is carried out is -60 to 80°C. The upper limit for the temperature is determined in part by the boiling point of the compound (R'_nD-R-Sul) and the boiling point of the solvent.

If D is a nitrogen atom, the compound according to the formula (DR'_n-R-Sul) is formed in situ by reacting an aminoalcohol compound (R'₂NR-0H) consecutively with a base (such as described above), potassium or sodium and a sulphonyl halide (Sul-X).

During the synthesis process according to the invention, geminal products may in part be formed. A geminal substitution is a substitution in which the number of substituents increases by 1, but in which the number of substituted carbon atoms does not increase. The amount of geminal products formed is low if the synthesis is carried out starting from a substituted Cp compound containing 1 substituent and increases as the substituted Cp compound contains more substituents. If sterically large substituents are present on the substituted Cp compound, geminal products are not, or are scarcely, formed. Examples of sterically large substituents are secondary or tertiary alkyl substituents.

The amount of geminal product formed is also low if the second step of the reaction is carried out under the influence of a Lewis base whose conjugated acid has a dissociation constant, pK_a, of -2.5 or less. The pK_a values are based on D. D. Perrin: Dissociation Constants of Organic Bases in Aqueous Solution, International Union of Pure and Applied Chemistry, Butterworths , London 1965. The values have been determined in aqueous H₂S0₄ solution. Ethers may be mentioned as examples of suitable Lewis bases.

If geminal products have formed during the process according to the invention, said products can easily be separated from the nongeminal products by converting the mixture of geminally and nongeminally substituted products into a salt by reaction with potassium,, sodium or a base, after which the salt is washed with a dispersant in which the salt of the nongeminal products is insoluble or sparingly soluble. The compounds mentioned above may be used as base.

Suitable dispersants are nonpolar dispersants, such as alkanes. Examples of suitable alkanes are: heptane and hexane. The substituted Cp compounds, of which at least one substituent has the form -RDR'_n, are very suitable for use as ligand in a metal complex.

The metal complexes with the Cp compounds as ligands are suitable as catalyst component. Said cata- lyst components are, together with a cocatalyst, used in the polymerization of olefins.

The invention will be explained further on the basis of examples, without being restricted thereto.

Examples Experimental section:

Reactions were followed in time with the aid of gas chromatography (GC type: Hewlett Packard 5890 Series II, provided with autosampler type HP6890 Series Injector, integrator type HP3396A and HP Crosslinked Methyl Silicon Gum (25 m x 0.32 mm x 1.05 μm) column with one of the following temperature programmes: 50°C (5 min), rate: 7.5°C/min, 250°C (29 minutes) or 150°C (5 min), rate: 7.5°C/min. 250°C (29 minutes). The products were characterized using GC-MS (type Fisons MD800, equipped with a quadrupole mass detector, autoinjector Fisons AS800 and CPSil8 column (30 m x 0.25 mm x 1 μm, low bleed) using one of the following temperature programmes: 50°C (5 min), rate: 7.5°C/min, 250°C (29 minutes) or 150°C (5 min), rate: 7.5°C/min, 250°C (29 minutes) and Bruker ACP200 NMR (^XH = 200 MHz; ¹³C = 50 MHz or Bruker ARX400 NMR (^XH = 400 MHz; ¹³C = 100 MHz). Complexes were characterized using a Kratos MS80 mass spectrometer or a Finnigan Mat 4610 mass spectrometer.

Example I

In-situ preparation of 2-(N,N-dimethylaminoethyl) tosylate

A solution of n-butyllithium in hexane (1 equivalent) was added at -10°C (dispensing time: 60 minutes) to a solution of 2-dimethylaminoethanol (1 equivalent) in dry THF under dry nitrogen in a three- neck round-bottom flask provided with a magnetic stirrer and a dropping funnel. After all the butyllithium had been added, the mixture was brought to room temperature and stirred for 2 hours. The mixture was then cooled (-10°C) , after which paratoluenesulphonyl chloride (1 equivalent) was added. The solution was then stirred for 15 minutes at this temperature before the solution was added to a cyciopentadienyl anion. Comparable tosylates can be prepared in an analogous way. In a number of the examples below, a tosylate is always coupled to alkylated Cp compounds. During this coupling, geminal coupling also takes place in addition to the required substitution reaction. In nearly all cases it was possible to separate the geminal isomers from the nongeminal isomers by converting the nongeminal isomers into their sparingly soluble potassium salt, followed by washing of said salt with a solvent in which said salt is not soluble or is sparingly soluble.

Example II

Example Ila: Preparation of tri(2- propyl)cyclopentadiene 180 g (2.25 mol) of clear 50% NaOH, 9.5 g

(23 mmol) of Aliquat 336 and 15 g (0.227 mol) of freshly cracked cyclopentadiene were combined in a double-walled reactor having a capacity of 200 ml and provided with a baffles (sic), cooler, top stirrer, thermometer and dropping funnel. The reaction mixture was vigorously stirred for several minutes at a speed of 1385 rpm. Then 84 g (0.68 mol) of 2-propyl bromide were added. During this process, the mixture was cooled with water. A few minutes after adding the 2-propyl bromide, the temperature rose approximately 10°C. It was demonstrated with GC that, approximately 30 minutes after adding all the 2-propyl bromide, (monosubstituted) 2-propylcyclopentadiene had formed. The reaction mixture was then heated to 50°C. After 2 hours, stirring was stopped and phase separation was awaited. The water layer was drained off and 180 g (2.25 mol) of fresh 50% NaOH were added. Stirring was then carried out for a further hour at 50°C. It was demonstrated with GC that, at that instant, between 90 and 95% of tri (2-propyl )cyclopentadiene was present in the mixture of disubstituted, trisubstituted and tetra- substituted cyclopentadiene. The product was distilled at 1.3 mbar and 77 - 78°C. After distillation, 31.9 g of tri (2-propyl )cyclopentadiene were obtained.

The characterization was carried out with the aid of GC , GC-MS, ¹³C- and ^-NMR.

Example lib: Preparation of (dimethylaminoethyl )tri (2- propyl )cyclopentadienylpotassium

A solution of 62.5 ml (1.6 M in n-hexane; 100 mmol) of n-butyllithium was added to a solution of 19.2 g (100 mmol) of triisopropylcyclopentadiene in 250 ml of THF at -60°C under a dry nitrogen atmosphere in a dry 500 ml three-neck flask having a magnetic stirrer. After heating to room temperature (in approximately 1 hour), stirring was carried out for a further 2 hours. After cooling to -60°C, a solution of dimethylaminoethyl tosylate (105 mmol) (Example I) prepared in situ was added in 5 minutes. The reaction mixture was heated to room temperature, after which stirring was carried out overnight. After adding water, the product was extracted with petroleum ether (40 -

60°C). The combined organic layer was dried (Na₂S0₄) and evaporated down under reduced pressure. The conversion was greater than 95%. The geminal product isomers were removed by converting the nongeminal isomers into the sparingly soluble (2-dimethylaminoethyl)triisopropyl- cyclopentadienylpotassium, after which the potassium salt was washed with hexane. The overall yield of product (starting from triisopropylcyclopentadiene) was approximately 55%. Example lie: Preparation of bis(dimethylaminoethyl)tri (2-propyl )cyclopentadiene

A solution of 62.5 ml (1.6 M in n-hexane; 100 mmol) of n-butyllithium was added to a solution of 19.2 g (100 mmol) of tri (2-propyl )cyclopentadiene in 250 ml of THF at -60°C under a dry nitrogen atmosphere in a dry 500 ml three-neck flask having a magnetic stirrer. After heating to room temperature (in approximately 1 hour), stirring was carried out for a further 2 hours. After cooling to -60°C, a solution of dimethylaminoethyl tosylate (105 mmol) (Example I) prepared in situ was added in 5 minutes. The reaction mixture was heated to room temperature, after which stirring was carried out overnight. After adding water, the product was extracted with petroleum ether (40 -

60°C). The combined organic layer was dried (Na₂S0₄) and evaporated down under reduced pressure. The conversion was greater than 95%. Some of the product obtained in this way (10.1 g; 38.2 mmol) was alkylated yet again under the same conditions with dimethylaminoethyl tosylate (39.0 mmol).

The bis(2-dimethylaminoethyl)tri(2- propyl)cyclopentadiene was obtained with a yield of 35% via column chromatography.

Example III

Example Ilia: Preparation of dicyclohexylcyclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with baffles, cooler, top stirrer, thermometer and dropping funnel was filled with 600 g of clear 50% NaOH (7.5 mol), after which cooling was carried out to 8°C. Then 20 g (49 mmol) of Aliquat 336 and 33 g (0.5 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 172 g of cyclohexyl bromide (1.05 mol) were added. During this process, the mixture was cooled with water. After stirring for 2 hours at room temperature, the reaction mixture was heated to 70°C, after which stirring was carried out again for 6 hours. It was demonstrated with GC that 79% of dicyclohexylcyclopentadiene was present at that instant. The product was distilled at 0.04 mbar and 110 - 120°C. After distillation, 73.6 g of dicyclohexylcyclopentadiene were obtained.

The characterization was carried out with the aid of GC, GC-MS, ¹³C- and Η-NMR.

Example lllb: Preparation of (dimethylaminoethyl )- dicyclohexylcyclopentadiene

A solution of n-butyllithium in hexane (18.7 ml; 1.6 mol/1; 30 mmol) was added dropwise to a cooled (0°C) solution of dicyclohexylcyclopentadiene (6.90 g; 30.0 mmol) in dry tetrahydrofuran (125 ml) under a nitrogen atmosphere in a 250 ml three-neck round-bottom flask provided with magnetic stirrer and dropping funnel. After stirring for 24 hours at room temperature, 30.0 mmol of 2-dimethylaminoethyl tosylate (Example I) prepared in situ were added. After stirring for 18 hours, the conversion was found to be 88% and water (100 ml) was carefully added dropwise to the reaction mixture, after which the tetrahydrofuran was distilled off. The crude product was extracted with ether, after which the combined organic phase was dried (sodium sulphate) and evaporated down. The residue was purified by means of a column containing silica gel resulting in 7.4 g of (dimethylaminoethyl)dicyclohexyl- cyclopentadiene. Exampl e IV

Example IVa: Preparation of a di- and tri(2- pentyl )cyclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with baffles, cooler, top stirrer, thermometer and dropping funnel was filled with 900 g (11.25 mol) of clear 50% NaOH. Then 31 g (77 mmol) of Aliquat 336 and 26.8 g (0.41 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 155 g

(1.03 mol) of 2-pentyl bromide were added in one hour. During this process, the mixture was cooled with water. After stirring for 3 hours at room temperature, the reaction mixture was heated to 70°C, after which stirring was carried out again for 2 hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 900 g (11.25 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further two hours at 70°C. It was demonstrated with GC that the mixture was composed of di- and tri(2- pentyl)cyclopentadiene (approximately 1:1) at that instant. The products were distilled at respectively 2 mbar, 79-81°C and 0.5 mbar, 102°C. After distillation, 28 g of di- and 40 g of tri(2-pentyl)cyclopentadiene were obtained.

The characterization was carried out with the aid of GC, GC-MS, ¹³C- and tø-NMR.

Example IVb: Preparation of (dimethylaminoethyl)di(2- pentyl)cyclopentadiene

A solution of n-butyllithium in hexane (24.0 ml? 1.6 mol/1; 38 mmol) was added dropwise to a cooled (0°C) solution of di-2-pentylcyclopentadiene (7.82 g; 38.0 mmol) in dry tetrahydrofuran (125 ml) under a nitrogen atmosphere in a 250 ml three-neck round-bottom flask provided with magnetic stirrer and dropping funnel. After stirring for 24 hours at room temperature, 2-dimethylaminoethyl tosylate (38.0 mmol) (Example I) prepared in situ was added. After stirring for 18 hours, the conversion was found to be 92% and water (100 ml) was carefully added dropwise to the reaction mixture, after which the tetrahydrofuran was distilled off. The crude product was extracted with ether, after which the combined organic phase was dried (sodium sulphate) and evaporated down. The residue was purified using a column containing silica gel, resulting in 8.2 g of (dimethylaminoethyl)di-2- pentylcyclopentadiene.

Example IVc: Preparation of (dimethylaminoethyl)tri ( 2- pentyl)cvclopentadiene The reaction was carried out in the same way as for (dimethylaminoethyl)tri(2-propyl)cyclopentadiene (Example lib). The conversion was 90%. The nongeminal (dimethylaminoethyl)tri(2-pentyl)cyclopentadiene was obtained distillatively in a yield of 54%. The (dimethylaminoethyl)tri(2-pentyl)cyclopentadiene was obtained after preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, with a yield of 57%.

Example IVd: Preparation of di(n-butylaminoethyl)tri ( 2- pentyl)cyclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl)tri(2-propyl)cyclopentadiene (Example lib), the tosylate of N,N-di-n- butylaminoethanol being prepared in situ. The conversion was 88%. The 2-(di-n-butylaminoethyl)di(2- pentylJcyclopentadiene was obtained after preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, followed by distillation under reduced pressure, with a yield of 51%. Example V

Example Va: Preparation of di(2-propyl)cvclopentadiene

180 g of clear 50% NaOH (2.25 mol), 9.5 g (23 mmol) of Aliquat 336 and 15 g (0.227 mol) of freshly cracked cyclopentadiene were combined in a double-walled reactor having a capacity of 200 ml and provided with baffles, cooler, top stirrer, thermometer and dropping funnel. The reaction mixture was vigorously stirred for several minutes at a speed of 1385 rpm. Then 56 g (0.46 mol) of 2-propyl bromide were added. During this process, the mixture was cooled with water. Several minutes after adding the 2-propyl bromide, the temperature rose approximately 10°C. Then stirring was carried out for 6 hours at 50°C. It was demonstrated with GC that 92% di(2- propyl)cyclopentadiene was present in the mixture of di- and tri(2-propyl)cyclopentadiene at that instant. The product was distilled at 10 mbar and 70°C. After distillation, 25.35 g of di(2-propyl)cyclopentadiene were obtained. The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^XH-NMR.

Example Vb: Preparation of (dimethylaminoethyl)di (2- propyl)cvclopentadiene The reaction was carried out in the same way as for (dimethylaminoethyl)tri(2-propyl)cyclopentadiene (Example lib). The conversion was 97%. The (dimethyl¬ aminoethyl)di(2-propyl)cyclopentadiene was obtained distillatively with a yield of 54%.

Example Vc: Preparation of (di-n-butylaminoethyl)di(2- propyl)cvclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl)tri(2-propyl)cyclopentadiene (Example lib), the tosylate of N,N-di-n-butylamino- ethanol being prepared in situ. The conversion was 94%. The nongeminal di(n-butylaminoethyl)di(2- propyl)cyclopentadiene was obtained distillatively with a yield of 53%.

Example VI Example Via: Preparation of di (2-butyl )cvclopentadiene A double-walled reactor having a capacity of 1 1 and provided with baffles, cooler, top stirrer, thermometer and dropping funnel was filled with 600 g of clear 50% NaOH (7.5 mol), after which the contents were cooled to 10°C. Then 30 g of Aliquat 336 (74 mmol) and 48.2 g (0.73 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 200 g (1.46 mol) of 2-butyl bromide were added in half an hour. During this process, the mixture was cooled with water. After stirring for 2 hours at room temperature, the reaction mixture was heated to 60°C, after which stirring was carried out again for 4 hours. It was demonstrated with GC that more than 90% of di(2- butyl )cyclopentadiene was present in the mixture at that instant. The product was distilled at 20 mbar and 80 - 90°C. After distillation, 90.8 g of di(2- butyl Jcyclopentadiene were obtained.

The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^XH-NMR.

Example VIb: Preparation of (dimethylaminoethyl)di(2- butyl)cyclopentadiene

A solution of n-butyllithium in hexane (31.2 ml; 1.6 mol/1; 50 mmol) was added dropwise to a cooled (0°C) solution of di (2-butyl )cyclopentadiene (8.90 g; 50.0 mmol) in dry tetrahydrofuran (150 ml) under a nitrogen atmosphere in a 250 ml three-neck round-bottom flask provided with magnetic stirrer and dropping funnel. After stirring for 24 hours at room temperature, the 2-dimethylaminoethyl tosylate (50.0 mmol) (Example I) was added. After stirring for 18 hours, the conversion was found to be 96% and water (100 ml was carefully added dropwise to the reaction mixture, after which the tetrahydrofuran was distilled off. The crude product was extracted with ether, after which the combined organic phase was dried (sodium sulphate) and evaporated down. The residue was purified using a silica gel column, resulting in 8.5 g of (dimethylaminoethyl )di (2-butyl Jcyclopentadiene.

Example VII

Example Vila: Preparation of tri(2- butyl )cyclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with baffles, cooler, top stirrer, thermometer and dropping funnel was filled with 400 g (5.0 mol) of clear 50% NaOH . Then 9.6 g (24 mmol) of Aliquat 336 and 15.2 g (0.23 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 99.8 g (0.73 mol) of 2-butyl bromide were added in half an hour. During this process, the mixture was cooled with water. After stirring for half an hour at room temperature, the reaction mixture was heated to 70°C, after which stirring was carried out again for three hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 400 g (5.0 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further 2 hours at 70°C. It was demonstrated with GC that more than 90% tri(2- butyl )cyclopentadiene was present in the mixture of di- , tri- and tetra(2-butyl)cyclopentadiene at that instant. The product was distilled at 1 mbar and 91°C. After distillation, 40.9 g of tri(2- butyl )cyclopentadiene were obtained. The characteriz- ation was carried out with the aid of GC, GC-MS, ¹³C- and ^XH-NMR. Example Vllb: Preparation of (dimethylaminoethyl)tri(2- butyl)cvclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl)tri(2-propyl)cyclopentadiene (Example lib). The conversion was 92%. The product was obtained distillatively with a yield of 64%.

Example VIII

Example Villa: Preparation of di- and tri(3- pentyl)cvclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with baffles, cooler, top stirrer, thermometer and dropping funnel was filled with 430 g (5.4 mol) of clear 50% NaOH. Then 23 g (57 mmol) of Aliquat 336 and 27 g (0.41 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 150 g (1.0 mol) of 3-pentyl bromide were added in one hour. During this process, the mixture was cooled with water. After stirring for 1 hour at room temperature, the reaction mixture was heated to 70°C, after which stirring was again carried out for 3 hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 540 g (6.70 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further 4 hours at 70°C. It was demonstrated with GC that the mixture was composed of di- and tri(3- pentyl)cyclopentadiene (approx. 3:2) at that instant. The products were distilled at, respectively, 0.2 mbar, 51°C and 0.2 mbar, 77 - 80°C. After distillation, 32 g of di- and 18 g of tri(3-pentyl)cyclopentadiene were obtained.

The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^-NMR. Example Vlllb: Preparation of (dimethylaminoethyl )di (3- pentyl )cyclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl )tri(2-propyl)cyclopentadiene (Example lib). The conversion was 99%. The (dimethy¬ laminoethyl )di (3-pentyl )cyclopentadiene was obtained after preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, with a yield of 85%.

Example VIIIc: Preparation of (di-n-butylaminoethyl )- di (3-pentyl )cyclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl)tri(2-propyl)cyclopentadiene (Example lib), the tosylate of N,N-di-n- butylaminoethanol being prepared in situ. The conversion was 95%. The product was obtained after preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, with a yield of 75%.

Example Vllld: Preparation of (2-dimethylaminoethyl) tri (3-pentyl )cyclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl)tri(2-propyl)cyclopentadiene (Example lib). The conversion was 94%. The (2-dimethyl¬ aminoethyl )tri (3-pentyl )cyclopentadiene was obtained after preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, with a yield of 61%.

Example IX

Example IXa: Preparation of di(2- propyl)cyclohexylcyclopentadiene 150 g of clear 50% NaOH (1.9 mol), 7 g

(17.3 mmol) of Aliquat 336 and 8.5 g (0.13 mol) of freshly cracked cyclopentadiene were combined in a double-walled reactor having a capacity of 200 ml and provided with baffles, cooler, top stirrer, thermometer and dropping funnel. The reaction mixture was vigorously stirred for several minutes at a speed of 1385 rpm. Then 31.5 g (0.26 mol) of 2-propyl bromide were added. During this process, the mixture was cooled with water. The total dispensing time was 1 hour. After adding the bromide, the reaction mixture was heated to 50°C. After 2 hours, stirring was stopped and phase separation was awaited. The water layer was drained off and 150 g (1.9 mol) of fresh 50% NaOH were added. Then 20.9 g (0.13 mol) of cyclohexyl bromide were added, after which stirring was carried out for 3 hours at 70°C. It was demonstrated with GC that 80% di(2- propyl )cyclohexylcyclopentadiene was present in the mixture at that instant. The product was distilled at 0.3 mbar and 80°C. After distillation, 17.8 g of di(2- propyl )cyclohexylcyclopentadiene were obtained. The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^-NMR.

Example IXb: Preparation of cyclohexyl (dimethylamino¬ ethyl )di (2-propyl )cvclopentadiene

A solution of n-butyllithium in hexane (25.0 ml; 1.6 mol/1; 40.0 mmol) was added dropwise to a solution of cyclohexyldiisopropylcyclopentadiene (9.28 g; 40.0 mmol) in dry THF (150 ml) at room temperature in a Schenk vessel. Then a solution of n-butyllithium in hexane (25.0 ml; 1.6 mol/1; 40.0 mmol) was added dropwise to a cold (-78°C) solution of dimethylaminoethanol (3.56 g; 40.0 mmol) in THF (100 ml) in another Schenk vessel. After stirring for an hour and a half at room temperature, the mixture was again cooled to -78°C and solid p-toluenesulphonyl chloride (8.10 g; 40.0 mmol) was added slowly. The mixture was brought to 0°C and stirred at that temperature for 5 minutes, again cooled to -78°C, after which the mixture from the first Schenk vessel was added all at once. After stirring for 16 hours at room temperature, the conversion was 100%. After column chromatography, 11.1 g of cyclo- hexyl ^dimethylaminoethyl)di(2-propyl)cyclopentadiene were obtained.

Example X

Example Xa: Preparation of tri (cyclohexyl)cyclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with baffles, cooler, top stirrer, thermometer and dropping funnel was filled with 600 g (7.5 mol) of clear 50% NaOH, after which the mixture was cooled to 8°C. Then 20 g (49 mmol) of Aliquat 336 and 33 g (0.5 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 256 g (1.57 mol) of cyclohexyl bromide were added. During this process, the mixture was cooled with water. After stirring for 1 hour at room temperature, the reaction mixture was heated to 70°C, after which stirring was carried out again for 2 hours. After 2 hours, stirring was stopped and phase separation was awaited. The water layer was drained off and 600 g (7.5 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further 4 hours at 70°C. It was demonstrated with GC that 10% di- and 90% tri(cyclohexyl)cyclopentadiene were present in the mixture at that instant. The product was distilled at 0.04 mbar and 130°C. After distillation, 87.4 g of tri (cyclohexyl)cyclopentadiene were obtained.

The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^XH-NMR. Example Xb: Preparation of

(dimethylaminoethyl ) tr i cyclohexyl cyclopentadiene

The reaction was carried out in the same way as for (dimethylaminoethyl )tr i (2-propyl )cyclopentadiene (Example lib). The conversion was 91%. The product was obtained as eluent via preparative silica gel column purification using petroleum ether (40 - 60°C) and THF consecutively, in a yield (hiatus? translator).

Example XI

Example XIa: Preparation of tetraethylcvclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with a baffle, cooler, top stirrer, thermometer and dropping funnel was filled with 1050 g (13.1 mol) of clear 50% NaOH, after which the mixture was cooled to 10°C. Then 32 g (79 mmol) of Aliquat 336 and 51 g (0.77 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 344 g (3.19 mol) of ethyl bromide were added gradually in 1 hour. During this process, the mixture was cooled with water. After stirring for 1 hour at room temperature, the reaction mixture was heated to 35°C, after which stirring was carried out again for 6 hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 1050 g (13.1 mol) of fresh 50% NaOH were added. Stirring was then carried out for a further 5 hours at room temperature. It was demonstrated with GC that 15% tri-, 78% tetra- and 7% pentaethylcyclopentadiene were present in the mixture at that instant. The product was distilled at 11 mbar and 91°C. After distillation, 74.8 g of tetraethyl- cyclopentadiene were obtained. The characterization was carried out with the aid of GC, GC-MS, ¹³C- and ^XH-NMR. Example Xlb: Preparation of (dimethylaminoethyl)- tetraethylcyclopentadiene

A solution of n-butyllithium in hexane (6.00 ml; 1.65 mol/1; 9.90 mmol) was added dropwise to a solution of tetraethylcyclopentadiene (2.066 g; 11.6 mmol) in dry THF (20 ml) in a Schenk vessel at room temperature.

Then a solution of n-butyllithium in hexane (5.90 ml; 1.65 mol/1; 9.74 mmol) was added dropwise to a cold solution (-78°C) of 2-dimethylaminoethanol

(0.867 g; 9.74 mmol) in THF (35 ml) in a second Schenk vessel. After stirring for two hours at room temperature, the mixture was again cooled to -78°C and the solid p-toluenesulphonyl chloride (1.855 g; 9.74 mmol) was added slowly. The mixture was brought to 0°C and stirred at that temperature for 5 minutes, after which the mixture from the first Schenk vessel was added all at once. After 16 hours, the conversion was 100%. After column chromatography, 2.6 g of (dimethylaminoethyl)tetraethylcyclopentadiene was ob¬ tained.

Example XII

Example Xlla: Preparation of tetraoctylcyclopentadiene A double-walled reactor having a capacity of

1.5 1 and provided with baffles, cooler, top stirrer, thermometer and dropping funnel was filled with 900 g (11.3 mol) of clear 50% NaOH, after which the mixture was cooled to 10°C. Then 30 g (74 mmol) of Aliquat 336 and 48 g (0.72 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 577 g (2.99 mol) of octyl bromide was added in 1 hour. During this process, the mixture was cooled with water. After stirring for 1 hour at room temperature, the reaction mixture was heated to 35°C, after which stirring was carried out again for 6 hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 920 g (11.5 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further 5 hours at room temperature. It was demonstrated with GC that 10% tri-, 83% tetra- and 7% pentaoctylcyclopentadiene were present in the mixture at that instant. The product was distilled at reduced pressure. After vacuum distillation, 226.6 g of tetraoctylcyclopentadiene were obtained. The product was characterized with the aid of

GC, GC-MS, ¹³C- and ^-NMR.

Example Xllb: Preparation of

(dimethylaminoethyl)tetra(n-octyl)cyclopentadiene A solution of n-butyllithium in hexane (24.8 ml; 1.6 mol/1; 39.6 mmol) was added dropwise at room temperature to a solution of tetra(n- octyl)cyclopentadiene (20.4 g; 39.6 mmol) in dry THF (100 ml) in a Schenk vessel. Then a solution of n-butyllithium in hexane

(24.6 ml; 1.6 mol/1; 39.6 mmol) was added dropwise to a cold solution (-78°C) of 2-dimethylaminoethanol (3.53 g; 39.6 mmol) in THF (30 ml) in a second Schenk vessel. After stirring for two hours at room temperature, the mixture was again cooled to -78°C and the solid p- toluenesulphonyl chloride (7.54 g; 39.6 mmol) was added slowly. The mixture was brought to 0°C and stirred at that temperature for 5 minutes, after which the mixture from the first Schenk vessel was added all at once. After 16 hours, the conversion was 87%. After column chromatography, 19.2 g of (dimethylaminoethyl)tetra(n- octyl)cyclopentadiene were obtained.

Example XIII Example Xllla: Preparation of tetrapropylcyclopentadiene

A double-walled reactor having a capacity of 1 1 and provided with a baffle, cooler, top stirrer, thermometer and dropping funnel was filled with 1000 g (12.5 mol) of clear 50% NaOH, after which the mixture was cooled to 10°C. Then 30 g (74 mmol) of Aliquat 336 and 50 g (0.75 mol) of freshly cracked cyclopentadiene were added. The reaction mixture was vigorously stirred for several minutes. Then 373 g (3.03 mol) of propyl bromide were added in one hour. During this process, the mixture was cooled with water. After stirring for 1 hour at room temperature, the reaction mixture was heated to 35°C, after which stirring was carried out again for 6 hours. Stirring was stopped and phase separation was awaited. The water layer was drained off and 990 g (12.4 mol) of fresh 50% NaOH were added. Then stirring was carried out for a further 5 hours at room temperature. It was demonstrated with GC that 14% tri-, 80% tetra- and 6% pentapropylcyclopentadiene were present in the mixture at that instant. The product was distilled under reduced pressure. After vacuum distillation, 103.1 g of tetrapropylcyclopentadiene were obtained.

The product was characterized with the aid of GC, GC-MS, ¹³C- and ^XH-NMR.

Example Xlllb: Preparation of (dimethylaminoethyl )- tetra(n-propyl)cyclopentadiene

A solution of n-butyllithium in hexane (93.8 ml; 1.6 mol/1; 150 mmol) was added dropwise to a solution of tetra(n-propyl )cyclopentadiene (35.0 g; 150 mmol) in dry THF (200 ml) at room temperature in a 500 ml three-neck flask.

Then a solution of n-butyllithium in hexane (93.8 ml; 1.6 mol/1; 150 mmol) was added dropwise to a cold solution (-78°C) of 2-dimethylaminoethanol (13.35 g; 150 mmol) in THF (100 ml) in a second Schenk vessel. After stirring for 2 hours at room temperature, the mixture was again cooled to -78°C and the solid p- toluenesulphonyl chloride (28.5 g; 150 mmol) was added slowly. The mixture was brought to -20°C and stirred at that temperature for 5 minutes, after which the mixture from the first Schenk vessel was added. After 16 hours, the conversion was 97%. After column chromatography, 39.6 g of (dimethylaminoethyl )tetra(n- propyl )cyclopentadiene was obtained.

Example XIV Preparation of (2- phenoxyethyl )tetramethylcyclopentadiene

A solution of 2-phenoxyethanol (102.6 g; 0.744 mol) in THF (70 ml) was added (dispensing time: 35 minutes) to a solution of para toluenesulphonyl chloride (141.5 g; 0.743 mol) and triethylamine (149.6 g; 1.48 mol) in THF (400 ml) in a one-litre three-neck round-bottom flask provided with a dropping funnel. After stirring for two weeks (conve¬ rsion: 88%) the suspension was filtered. The filtrate was evaporated down, suspended in petroleum ether (40 - 60°C) and filtered again. The solid substance contained one equivalent of water ^H-NMR) and was therefore dried for 13 days at reduced pressure in a desiccator over phosphorus pentoxide. The yield was 161.6 g, which still contained 9 mol % of water.

A solution of n-butyllithium (63 ml; 1.6 mol/1; 0.10 mol) was added dropwise to a solution of tetramethylcyclopentadiene (12.2 g; 0.10 mol) mmol) (sic) in ether (500 ml) in 35 minutes at 2°C in a one- litre three-neck round-bottom flask provided with mechanical top stirrer and dropping funnel. This mixture was stirred overnight at room temperature, after which the tosylate of 2-phenoxyethanol (29.5 g? 0.10 mol) was added in one hour. After stirring for two days, water (80 ml) was added to the reaction mixture. The organic phase was separated from the water layer, dried with sodium sulphate and evaporated down. The residue was distilled under reduced pressure, resulting in 20.7 g of product.

A solution of n-butyllithium (10.8 ml; 1.6 mol/1; 17.3 mmol) was added dropwise to a solution of (2-phenoxyethyl )tetramethylcyclopentadiene in diethyl ether under a nitrogen atmosphere in a 250 ml three- neck round-bottom flask provided with magnetic stirrer. After stirring for one hour at room temperature, the 5- (2-phenoxyethyl)-l,2,3,4- tetramethylcyclopentadienyllithium was crystallized at -80°C, filtered directly under nitrogen and then washed twice with petroleum ether. After drying, 14.2 g of the lithium salt was obtained.

Example XV

Preparation of (isopropoxyethyltetramethyl¬ cyclopentadiene

A solution of n-butyllithium in hexane (35 ml; 1.6 mol/1; 56 mmol) was added dropwise to a solution of tetramethylcyclopentadiene (6.24 g; 51 mmol) in diethyl ether under a nitrogen atmosphere in a 250 ml three-neck round-bottom flask provided with a dropping funnel. After stirring for 16 hours at room temperature, the tosylate of 2-isopropoxyethanol (14.01 g; 57 mmol) was added all at once. After stirring for 16 hours at room temperature, the reaction mixture was filtered, after which the precipitate was washed with diethyl ether. The combined organic layer was evaporated down and the residue was distilled under reduced pressure, resulting in 6.06 g of product.

The crude product isopropoxyethyltetramethyl- cyclopentadiene was added dropwise to a cooled (0°C) suspension of potassium hydride (0.55 g; 12.3 mmol) in THF (100 ml) under a nitrogen atmosphere in a three- neck round-bottom flask. After stirring for half an hour at 0°C, the mixture was slowly brought to room temperature (in four hours). After stirring for one night at room temperature, the solid substance was filtered off under nitrogen and washed with petroleum ether (40 - 60°C) (twice with 100 ml), resulting in 3.22 g of 5-isopropoxyethyl-l,2,3,4- tetramethylcyciopentadienylpotassium.

Example XVI

Preparation of methoxyethyltetramethylcvclopentadiene A three-neck flask was filled with 12.4 g of 1,2,3,4-tetramethylcyclopentadiene (0.10 mol) dissolved in 350 ml of ether. The solution was cooled to 2°C, after which 63 ml of n-butyllithium (1.6 M in hexane, 0.10 mol) was added dropwise. Stirring was then carried out for 18 hours at room temperature. A solution of 23.5 g (0.10 mol) of 2-methoxyethyl tosylate in 25 ml of ether was added dropwise to this solution in a period of approximately 15 minutes and stirring was then carried out for 18 hours at room temperature. Then 50 ml of water was added dropwise. Water phase and organic phase were separated. The water layer was extracted 2^χ with ether. The combined ether layers were dried over magnesium sulphate. The magnesium sulphate was filtered off and the filtrate evaporated down. The residue (17.0 g) contained 1,2,3,4-tetramethyl-5-(2- methoxyethyl)cyclopentadiene. After gas-chromatographic analysis of the crude reaction mixture, it was found that the conversion of tosylate and tetramethylcyclopentadiene was 100%.

Claims

C L A I M S

1. Process for substituting a cyclopentadiene with at least one group of the form -RDR'_n by deprotonating cyclopentadiene already substituted with at least one other group through reaction with a base, sodium or potassium and then reacting the cyciopentadienyl anion formed with a compound containing a sulphonyl group, characterized in that the sulphonyl-group-containing compound is a compound according to the formula (R '_nD-R-Sul) , wherein

R is a linking group, R' is a substituent,

D is a heteroatom from group 15 or 16 of the Periodic System of the Elements and Sul is a sulphonyl group.

2. Process according to claim 1, in which the process is carried out under the influence of a Lewis base whose conjugated acid has a dissociation constant, pK_a, of -2.5 or less.

3. Process according to any one of claims 1-2, in which R has the structure (-ER² ₂-)_p where p = 1-4 and E is an atom from group 14 of the Periodic System.

4. Process according to any one of claim 1-2, in which R has the structure -CR² ₂-(ER² ₂-)_p.₁ in which p = 1-4 and E is an atom from group 14 of the Periodic System.

5. Process according to any one of claims 1-4, in which D is chosen from the group comprising nitrogen (N) , oxygen (0), phosphorus (P) or sulphur (S).

6. Process according to any one of claims 1-5, in which R' is an N-alkyl group containing 1-20 C- atoms.

7. Process according to any one of claims 1-6, in which the sulphonyl group is p-toluene sulphonyl or trifluoromethanesulphonyl .

8. Process according to Claim 1, characterized in that the product obtained with the process according to Claim 1 is converted into a salt by reaction with potassium, sodium or a base, after which said salt is washed with a dispersant in which the salt of the nongeminal products hardly dissolves.