Process for the preparation of cyclopentadienyl metal salt...

Details Process for the preparation of cyclopentadienyl metal salt... Process for the preparation of cyclopentadienyl metal salt...

1999-07-13

2001-03-06

Nazario-Gonzalez, Porfirio (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Silicon containing

C556S087000, C585S350000, C585S313000

Reexamination Certificate

active

06197990

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for the preparation of a cyclopentadienyl metal salt and a process for the preparation of a cyclopentadiene derivative using the same.
BACKGROUND ART
Cyclopentadienyl metal salts and derivatives of cyclopentadiene derived from such metal salts are important intermediates which are used in various fields such as the preparation of medicines, agrochemicals, metallocenes, etc. An effective process for the preparation of cyclopentadienyl metal salts comprises removing hydrogen atoms from cyclopentadiene with bases to synthesize corresponding metal salts, and for example, such a process using butyl lithium is known (J. Organomet. Chem., 462, 1993, 57-67).
However, the process using butyl lithium has disadvantages such that (1) used reagents are expensive, (2) it requires low-temperature facilities to perform the reaction, and (3) the reaction should be carried out at the low concentration of reagents in an industrial scale, and thus the productivity decreases, since the desired product cannot effectively be obtained if the reaction is not carried out at a low temperature, although the amount of reaction heat is large. As a matter of course, cyclopentadiene derivatives derived from cyclopentadienyl metal salts have the same problems.
Also, a process using an alkali metal hydride is known. However, this process has disadvantages such that (1) the kinds of substrates are extremely limited, (2) mineral oils, which are usually contained as a stabilizer in marketed alkali metal hydrides, should be beforehand removed, and thus the use of the alkali metal hydrides is unfavorable from the viewpoint of disaster measures, and the number of process steps in the industrial production.
DISCLOSURE OF THE INVENTION
In view of the above circumstances, the present inventors extensively studied a process which can easily produce a cyclopentadienyl metal salt without the use of expensive reagents and low-temperature facilities, and has no substrate specificity. As a result, it has been found that such an object can be accomplished by the reaction of a cyclopentadiene and a metal hydride in the presence of an amine compound, and thus the present invention has been completed.
Accordingly, the present invention provides
1. a process for the preparation of a cyclopentadienyl metal salt comprising the step of reacting a cyclopentadiene and a metal hydride in the presence of an amine compound, and
2. a process for the preparation of a cyclopentadiene derivative of the formula (3):
wherein
A is an atom of the 16 group of the Periodic Table,
B is an atom of the 14 group of the Periodic Table,
R
1
, R
2
, R
3
, R
4
, R
5
and R
6
are the same or different and independently represent a hydrogen atom, a fluorine atom, a C
1
-C
20
alkyl group which may optionally be substituted with a fluorine atom, a C
7
-C
20
aralkyl group which may optionally be substituted with a fluorine atom, a C
6
-C
20
aryl group which may optionally be substituted with a fluorine atom, a C
1
-C
20
substituted silyl group, a C
1
-C
20
alkoxyl group which may optionally be substituted with a fluorine atom, a C
7
-C
20
aralkyloxyl group which may optionally be substituted with a fluorine atom, a C
6
-C
20
aryloxyl group which may optionally be substituted with a fluorine atom, or a C
2
-C
20
di-substituted amino group which may optionally be substituted with a fluorine atom, provided that any two or more of R
1
, R
2
, R
3
, R
4
, R
5
and R
6
may together form a ring,
R
7
is a hydrocarbon group which may optionally be substituted with a fluorine atom, or a tri-substituted silyl group, and
Cp is a cyclopetadiene ring comprising the step of reacting a halide compound of the formula (1):
wherein A, B, R
1
, R
2
, R
3
, R
4
, R
5
, R
6
and R7 are the same as defined above, and Y
1
is a chlorine atom, a bromine atom or an iodine atom
with a cyclopentadiene of the formula (2):
HCp  (2)
wherein Cp is the same as defined above, in the presence of a metal hydride and an amine compound.
Here, the process according to the first aspect of the present invention, that is, the preparation process of a cyclopentadienyl metal salt by the reaction of a cyclopentadiene and a metal hydride in the presence of an amine compound, will be explained.
Cyclopentadienes used in the present invention may be any compounds having a cyclopentadienyl moiety. For example, a cyclopentadiene of the formula (2), which is used in the processes according to the first and second aspects of the present invention, may be a compound of the formula (2a):
wherein m is an integer of 0 to 5, E groups are the same or different and independently represent a C
1
-C
8
alkyl group, a phenyl group, a naphthyl group, or a tri-substituted silyl group having substituents selected from the group consisting of a C
1
-C
4
alkyl group and a phenyl group, provided that, when two E groups are present on adjacent carbon atoms, they may be bonded at their ends to form a benzene ring, a cyclohexane ring or a cyclohexene ring, which is condensed with the cyclopentadienyl ring,
G is a hydrogen atom when m is 5, or when m is 0 to 4, G is a hydrogen atom or a group of the formula (2b):
wherein p is an integer of 1 or 2, q is an integer of 0 to 4, X
0
is a carbon atom or a silicon atom, X
1
and X
2
are the same or different and independently represent a hydrogen atom, a C
1
-C
4
alkyl group or a phenyl group, E′ is a substituent selected from those defined for E, provided that when X
0
is a silicon atom, X
1
and X
2
are not hydrogen atoms.
Herein, the cyclopentadienyl group includes a mixture of its tautomers, which is usually obtained. The chemical structures in this specification represent a part of tautomers as typical examples.
Examples of cyclopentadienes, which are compounds having a cyclopentadienyl moiety, include
cyclopentadiene compounds such as cyclopentadiene, methylcyclopentadiene, dimethylcyclopentadiene, trimethylcyclopentadiene, tetramethylcyclopentadiene, pentamethylcyclopentadiene, ethylcyclopentadiene, n-propylcyclopentadiene, isopropylcyclopentadiene, n-butylcyclopentadiene, sec.-butylcyclopentadiene, tert.-butylcyclopentadiene, n-pentylcyclopentadiene, neopentylcyclopentadiene, n-hexylcyclopentadiene, n-octylcyclopentadiene, phenylcyclopentadiene, naphthylcyclopentadiene, trimethylsilylcyclopentadiene, triethylsilylcyclopentadiene, tert.-butyldimethylsilylcyclopentadiene, etc.;
indene compounds such as indene, methylindene, dimethylindene, ethylindene, n-propylindene, isopropyl indene, n-butylindene, sec.-butylindene, tert.-butylindene, n-pentylindene, neopentylindene, n-hexylindene, n-octylindene, n-decylindene, phenylindene, methylphenylindene, naphthylindene, trimethylsilylindene, triethylsilylindene, tert.-butyldimethylsilylindene, tetrahydroindene, etc.;
fluorene compounds such as fluorene, methylfluorene, ethylfluorene, n-propylfluorene, isopropylfluorene, n-butylfluorene, sec.-butylfluorene, tert.-butylfluorene, n-pentylfluorene, neopentylfluorene, n-hexylfluorene, n-octylfluorene, n-decylfluorene, n-dodecylfluorene, phenylfluorene, naphthylfluorene, trimethylsilylfluorene, triethylsilylfluorene, tert.-butyldimethylsilylfluorene, etc.;
biscyclopentadiene compounds such as biscyclopentadienylmethane, biscyclopentadienylethane, biscyclopentadienylpropane, biscyclopentadienylbutane, biscyclopentadienylpentane, biscyclopentadienylhexane, biscyclopentadienyldimethylsilane, biscyclopentadienyldiphenylsilane, bismethylcyclopentadienyldimethylsilane, bisdimethylcyclopentadienyldimethylsilane, bistrimethylcyclopentadienyldimethylsilane, bistetramethylcyclopentadienyldimethylsilane, biscyclopentadienyltetramethyldisilane, etc.;
bisindene compounds such as bisindenylmethane, bisindenylethane, bisindenylpropane, bisindenylbutane, bisindenylpentane, bisindenylhexane, bisindenyldimethylsilane, bisindenyldiphenylsilane, bismethylindenyldimethylsilane, bisdimethylindenyldimethylsilane, bisindenyltetramethyldisilane, etc.;
bisfluorene compounds such as bisfluorenylmathane, bisfluorenylethan

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