Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Utility Patent
1999-01-08
2001-01-02
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C556S012000, C556S018000, C556S022000, C556S028000, C556S143000, C556S144000, C502S154000, C502S155000, C502S158000
Utility Patent
active
06169192
ABSTRACT:
The invention relates to 1,2-ferrocenyldiphosphines which contain a functional group in the 1′ position either directly or via a bridging group, and also a process for their preparation. The compounds are important ligands for transition metal complexes containing d-8 metals such as Rh, Ru, Pd or Ir. These transition metal complexes are widely used in the hydrogenation of organic double or triple bonds, in particular olefinic double bonds and carbon-heteroatom double bonds. The complexes are particularly suitable for enantioselective hydrogenation using chiral ferrocenyldiphosphines and corresponding prochiral unsaturated compounds.
Ferrocenyldiphosphines having a functional group in the 1′ position are also important intermediates for ferrocenyldiphosphine ligands and their metal complexes of d-8 metals such as rhodium, ruthenium, palladium or iridium which are bound to inorganic or organic polymeric supports via this functional group. These metal complexes bound to an inorganic or organic support material are likewise very suitable for the hydrogenation of organic double or triple bonds.
The invention further provides extractable or adsorbable ferrocenyldiphosphines and ferrocenyldiphosphines having an adjusted solubility and catalysts comprising these ferrocenyldiphosphines, and also a process for preparing the compounds mentioned. These are either ferrocenyldiphosphines containing a functional group in the 1′ position or ferrocenyldiphosphines derived therefrom.
EP-A-0-496 699 and EP-A-0 496 700 describe dioxolane- and pyrrolidine-diphosphines containing silane groups and also their rhodium or iridium complexes which are fixed to an inorganic support material, for example a silicate. In a hydrogenation, these give a heterogeneous reaction mixture from which the inorganically fixed catalyst can easily be separated after the reaction is complete.
Monophosphines or diphosphines bound to polymers have likewise become known. They can be fixed in two fundamentally different ways:
a) by copolymerization of diphosphines bound to appropriate monomers and
b) by reaction of functionalized diphosphines with previously formed, functional polymers, either directly or via an additional bridging group.
Thus, for example, K. Achiwa in J. Chem. Japan Soc., Chemistry Letters, pages 905 to 908 (1978) describes polystyrene copolymers whose benzene rings contain rhodium-complexed pyrrolidine-diphosphine-N-carbonyl groups. The synthesis of the monomers is difficult and the hydrogenation of prochiral olefins using these heterogeneous catalysts is, compared with catalysts not bound to polymer, associated with a lowering of the activity, the productivity and the enantioselectivity. The pyrrolidine-diphosphine ligands are fixed via a para-amide bond directly to the benzene ring of the styrene which forms part of the copolymer while the other part of the copolymer framework is formed by hydroxyethyl methacrylate.
In J. of Organometallic Chemistry, 333 (1987), 269-280, W. R. Cullen et. al. describe ferrocene derivatives such as N,N-dimethyl-1-(2-diphenylphosphinoferrocenyl)ethylamine which is bound directly to an oxidized polystyrene group. In the procedure proposed there, a maximum of 20% of the ferrocene derivative used is bound to the polymeric support and the ferrocenyl ligand is unspecifically and unselectively, partly via one or the other cyclopentadienyl ring to the polymer.
Ferrocenes which are substituted by 2 phosphine groups only on one cyclopentadienyl ring have been known for a relatively long time. Their preparation and use as ligands in metal complexes for stereoselective hydrogenations is described, for example, in EP-A-564 406.
Recently, A. Togni in Chimia 50, (1996), 86-93 published the compound (A1)
which appears to be able to be prepared in a complicated synthesis which builds up the cyclopentadienyl rings. The method of preparation is analogous to the process described in Organometallics 1994, 13, 4481-4493.
It has now been found that ferrocenyldiphosphines which contain a functional group bound either directly or via a bridging group to only one cyclopentadienyl ring can be prepared in a simple way and can be immobilized on both inorganic and organic polymeric support materials, and can also be used as extractable and/or adsorbable ligands/catalysts. They can be bound to a previously prepared polymer either directly or via a bridging group or they can be immobilized after introduction of a polymerizable group by copolymerization of the monomers thus obtained. With d
8
metals such as rhodium, ruthenium, palladium and iridium, the immobilized ferrocenyldiphosphine ligands form complexes which can be used as highly active catalysts in enantioselective hydrogenations of carbon—carbon, carbon-nitrogen, or carbon-oxygen double bonds. The selectivity and the total yield are surprisingly high for immobilized systems. In particular for imine hydrogenation, the iridium catalysts are particularly well suited since they have the clearly highest activity and the highest catalyst productivity in comparison with other immobilized systems. Their selectivity is likewise very good. The catalysts can easily be separated from the reaction solution and be reused. Virtually no metal and ligand losses occur. These immobilized catalysts therefore allow, in particular, industrial-scale hydrogenations to be carried out economically.
The reaction to be catalysed can, for example in the case of ferrocenyldiphosphine ligands bound to a polymer, even be carried out heterogeneously or homogeneously depending on the choice of the polymer. The polymer can be prepared or even subsequently specifically modified such that the catalyst bound to the polymer dissolves in the reaction medium, can easily be separated off after the reaction by filtration, ultrafiltration, extraction or adsorbtion to support materials and can then be reused. The catalysts can be reused a number of times. Selection of the polymer enables the catalyst to be matched optimally to the reaction medium during the hydrogenation step and then be completely separated off, which is particularly important for hydrogenations carried out on an industrial scale.
In all cases, the recovery of the noble metals present when the catalyst has to be replaced after frequent recycling is made easier. It is frequently also possible to omit further purification of the hydrogenated product since the catalyst can be removed virtually quantitatively.
The preparation of these immobilized or extractable and/or adsorbable ferrocenyldiphosphines has been made possible for the first time by the provision of appropriately functionalized ferrocenyldiphosphines. These intermediates and their preparation are therefore of great importance.
The invention provides compounds of the formula VI
R
1
is C
1
-C
8
alkyl, phenyl or phenyl substituted by from 1 to 3 C
1
-C
4
alkyl or C
1
-C
4
alkoxy;
R
10
, R
11
, R
12
and R
13
are, independently of one another, C
1
-C
12
alkyl, C
5
-C
12
cycloalkyl, phenyl, C
5
-C
12
cycloalkyl substituted by C
1
-C
4
alkyl or C
1
-C
4
alkoxy or phenyl substituted by from one to three C
1
-C
4
alkyl, C
1
-C
4
alkoxy, —SiR
4
R
5
R
6
, halogen, —SO
3
M, —CO
2
M, —PO
3
M, —NR
7
R
8
, —[
+
NR
7
R
8
R
9
]X
−
or C
1
-C
5
fluoroalkyl; or the groups
—PR
10
R
11
and —PR
12
R
13
are each, independently of one another, a radical of the formula IV, IVa, IVb or IVc
R
4
, R
5
and R
6
are, independently of one another, C
1
-C
12
alkyl or phenyl;
R
7
and R
8
are, independently of one another, H, C
1
-C
12
alkyl or phenyl or R
7
and R
8
together are tetramethylene, pentamethylene or 3-oxa-1,5-pentylene;
R
9
is H or C
1
-C
4
alkyl;
M is H or an alkali metal;
X
−
is the anion of a monobasic acid;
halogen is fluorine, chlorine, bromine or iodine; and
a) B is a direct bond and FU is a functional group bound via a carbon atom to the cyclopentadienyl; or
b) B is a bridging group bound via a carbon atom or a silicon atom to the cyclopentadienyl and FU is a functional group;
with the exception of the compound of t
Landert Heidi
Pugin Beno{circumflex over (i)}t
Nazario-Gonzalez Porfirio
Novartis AG
Wenderoth , Lind & Ponack, L.L.P.
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