Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
1998-12-11
2001-08-07
Killos, Paul J. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C562S462000, C564S428000, C568S327000, C568S440000, C568S652000, C568S929000, C568S930000
Reexamination Certificate
active
06271411
ABSTRACT:
The present invention relates to a novel process for preparing 2-aryl-substituted indenes, which are useful in the synthesis of metallocene compounds used in olefin polymerization. It is known that the use of metallocene compounds in propylene polymerization gives rise either to amorphous or to crystalline polymers depending on the metallocene used. In particular chiral, bridged metallocene compounds give rise to stereospecific catalysts able to polymerize propylene to highly crystalline polymers. EP-A-185,918 for instance discloses a process for the preparation of isotactic polypropylene in the presence of ethylene-bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride.
WO 95/25757 discloses a catalyst based on unbridged 2-aryl-substituted bis-indenyl metallocenes that permits to obtain partially crystalline thermoplastic-elastomeric stereoblock olefin polymers. The 2-aryl-indene ligands of said metallocenes are prepared by means of a Grignard reaction between 2-indanone and phenylmagnesium bromide and following elimination in acidic environment. Thus, 2-phenyl-1H-indene was prepared according to the following scheme:
with an overall yield of the two-step reaction of about 65%.
An improvement of the above preparation is disclosed in WO 96/20225. By carrying out the reaction between 2-indanone and phenylmagnesium bromide in the presence of a compound of a metal selected from lanthanum and those of the lanthanide series, particularly cerium chloride, 2-phenyl-1H-indene was obtained with an overall yield of the two-step reaction of about 75%.
However, both of the above mentioned PCT applications disclose the preparation of 2-aryl-indenes wherein the indenes have no other substituents in addition to the aryl group in 2-position. A reason therefore is that substituted 2-indanones are difficult to find commercially and are also difficult to prepare. In fact, the starting 2-indanone is obtained by a reaction of indene with formic peracid according to the following scheme:
This reaction is very dangerous and the yield is very low (about 40%).
Another limitation of the above preparation process is that it cannot be used to prepare 2-aryl-substituted indenes in which the aryl group has substituents which are not compatible with the Grignard reaction such as, for example, carboxyl or carbonyl groups.
There is therefore the need for a more practical process for the preparation of 2-arylindene compounds allowing to obtain these compounds in high yields and furthermore allowing the preparation of compounds whose synthesis was not possible according to the methods of the prior art.
Chem. Rev., 1989, 89, 1433-1445 describes the Heck coupling reaction of haloarenes with alkenes catalyzed by palladium(0). A proposed mechanism for the coupling of iodobenzene with styrene is the following:
According to this scheme, the reaction has to pass through the steps of cis-addition and cis-elimination. Thus, this reaction would not have been deemed allowed on substrates such as indene because the intermediate deriving from cis-addition to the double bond, i.e.:
does not allow cis-elimination.
It has now unexpectedly been found that, by operating under particular conditions, it is possible to prepare 2-aryl-substituted indenes and 2-aryl-substituted, bridged bis-indenyls by reacting an indene with an arene compound having, a suitable leaving group.
Thus, according to a first aspect, the present invention provides a process for the preparation of 2-aryl-substituted indenes of the formula (I):
wherein:
R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
and R
9
, same or different, are hydrogen atoms, halogen atoms, C
1
-C
20
alkyl, C
3
-C
20
cycloalkyl, C
2
-C
20
alkenyl, C
6
-C
20
aryl, C
7
-C
20
alkylaryl, C
7
-C
20
arylalkyl, NO
2
, NR
10
2
, OH, OR
11
, COOH, COOR
12
, COH or COR
13
groups, optionally containing Si or Ge atoms, any two adjacent R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
and R
9
substituents optionally forming an aromatic or aliphatic ring comprising from 5 to 8 carbon atoms, and one of R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
and R
9
being optionally linked with a corresponding R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
, R
8
and R
9
of a second compound of the formula (I) to form a structural bridging group; R
10
, R
11
, R
12
and R
13
being C
1
-C
20
alkyl, C
3
-C
20
cycloalkyl, C
2
-C
20
alkenyl, C
6
-C
20
aryl, C
7
-C
20
alkylaryl or C
7
-C
20
arylalkyl radicals; optionally an aromatic carbon atom of the indene ring being replaced by a hetero atom selected from those belonging to group 15 of the Periodic Table of the Elements (new IUPAC version). the R
1
, R
2
, R
3
or R
4
substituent on the replaced carbon atom being absent, said process comprising the reaction of an indene of the formula (H):
wherein R
1
, R
2
, R
3
and R
4
have the meaning given above, one of R
1
, R
2
, R
3
and R
4
being optionally linked with a corresponding R
1
, R
2
, R
3
and R
4
of a second indene of the formula (II) to form a structural bridging group, optionally an aromatic carbon atom of the indene ring being replaced by a hetero atom selected from those belonging to group 15 of the Periodic Table of the Elements (new IUPAC version), the R
1
, R
2
, R
3
or R
4
substituent on the replaced carbon atom being absent; with an arene compound of the formula (E):
wherein X is an halogen atom, preferably a iodine atom, or an organosulphonate group, R
5
, R
6
, R
7
, R
8
and R
9
have the meaning given above, one of R
5
, R
6
, R
7
, R
8
and R
9
being optionally linked with a corresponding R
5
, R
6
, R
7
, R
8
and R
9
of a second arene compound of the formula (III) to form a structural bridging group; said reaction being carried out in a basic medium in the presence of a palladium catalyst.
The reaction of the invention has to be carried out in a basic medium. Suitable bases for use in the process of the present invention include:
primary, secondary or tertiary amines, such as thriethylamine;
alkali or earth-alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide;
alkali or earth-alkali metal carbonates or hydrocarbonates, such as sodium carbonate, potassium carbonate;
alkali or earth-alkali metal alcoholates, such as sodium ethylate, potassium tern-butylate;
quaternary ammonium hydroxides or alkoxides, such as tetrabutylammonium hydroxide tetrabutylammonium ethoxide.
The reaction of the invention can suitably by carried out in any solvent commonly used in this kind of reaction, such as dimethyl sulphoxide (DMSO), N,N-dimethylformamide (DMF), sulpholane, N-methylpyrrolidone, N,N-dimethylacetamide, tetrahydrofurane (THF), ethers, hexamethylphosphoramide.
According to a preferred embodiment, the reaction of the invention is carried out in the presence of a base which acts as a solvent. Bases suitable for this purpose are the tertiary amines such as the triethyl amine.
According to a more preferred embodiment, the reaction of the invention is carried out in a mixture containing a polar solvent and a tertiary amin.
According to a most preferred embodiment, the reaction of the invention is carried out in a mixture containing N,N-dimethylformamide (DMF) and triethyl amine.
In the reaction of the invention the volume ratio of the polar solvent to the tertiary amin can vary in a very wide range. Generally, the volume ratio of the polar solvent to the tertiary amin is in the range from 1:100 to 100:1. Thus, according to the preferred embodiments of the invention the content of the polar solvent can be varied from 1% to 99% by volume. By operating in a mixture containing in addition to the tertiary amine a polar solvent such as DMF a higher yield of the desired product can be obtained.
Palladium catalysts suitable for use in the reaction of the invention are palladium(0) and palladium(II) compounds such as, for example, the palladium (II) salts of mono- or dicarbossilic acids. A preferred palladium compound is palladium acetate.
In the arene compound of the formula (III), X is an halogen atom, preferably a iodine
Dubitsky Yuri A.
Nifant'ev Ilya E.
Sitnikov Alexander A.
Bryan Cave LLP
Killos Paul J.
Montell Technology Company BV
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