Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Patent
1997-10-09
1999-07-20
Shah, Mukund J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
556143, C07F 1702
Patent
active
059257784
DESCRIPTION:
BRIEF SUMMARY
This application is 371 of PCT/EP96/01439 filed Apr. 2, 1996
The invention relates to ferrocenes substituted in the 1,2- and 1'-positions and to processes for the preparation thereof.
Ferrocenyldiphosphine ligands having a silylene group are important intermediates for ferrocenyldiphosphines, and their metal complexes with transition metals such as rhodium or iridium, bonded via that silylene group to inorganic or polymeric organic carriers. Those complexes are used widely in the hydrogenation of organic double or triple bonds, especially olefinic double bonds and carbon-hetero atom double bonds. The complexes are suitable especially for enantioselective hydrogenation using chiral ferrocenyldiphosphines and corresponding prochiral unsaturated compounds.
EP-A-0-496 699 and EP-A-0 496 700 disclose silane-group-containing dioxolan- and pyrrolidine-diphosphines and their rhodium or iridium complexes that are fixed to an inorganic carrier such as, for example, a silicate. In that manner there is obtained in the hydrogenation a heterogeneous reaction mixture from which the inorganically fixed catalyst can readily be separated when the reaction is complete.
W. R. Cullen et. al. describe in J. of Organometallic Chemistry, 333 (1987), 269-280 ferrocene derivatives, such as, for example, N,N-dimethyl-1-(2-diphenylphosphino-ferrocenyl)ethylamine that is bonded directly to an oxidised polystyrene group. In the procedure proposed therein a maximum of 20% of the ferrocene derivative used is bonded to the polymeric carrier and the ferrocenyl ligand is bonded to the polymer non-specifically and non-selectively partly via one or the other cyclopentadienyl ring. As a result of the direct bonding to the polymer skeleton the mobility of the phosphine ligand is likewise restricted.
It appears desirable to start from starting materials having known properties and to modifiy those starting materials using catalytically active compounds in such a manner that the properties are altered only very slightly and there are no inclusions or any other alterations to the catalytically active part; depending on the hydrogenation reaction, either inorganically or organically bonded ferrocenyldiphosphine ligands may be more advantageous.
However, it is also possible further to functionalise those silylated ferrocenyldiphosphines in such a manner that they are copolymerisable, for example, via an olefinically unsaturated bond. Such procedures are described, for example, in J. Org. Chem. 1981, 46, 2960-2965.
In the case of polymer-bonded ferrocenyldiphosphine ligands, for example, the reaction to be catalysed can be carried out heterogeneously or homogeneously depending upon the polymer chosen. The polymer may be so selected and also subsequently so modified in a targeted manner that the catalyst can readily be separated off and re-used after the reaction. The catalysts may be re-used several times. By the choice of the polymer it is possible to match the catalyst in an optimum manner to the reaction medium during the hydrogenation step and then to remove it completely afterwards, which is of particular importance in relation to hydrogenation carried out on an industrial scale.
In all cases the recovery of the noble metals present is facilitated if the catalyst has to be changed after frequent recycling. It is often also possible to dispense with further purification of the hydrogenated product since the catalyst can generally be removed quantitatively.
Ferrocenyldiphosphines that contain an organic radical bonded via a silylene group to a cyclopentadienyl ring can be immobilised in a simple manner both on inorganic and on polymeric organic carriers or, after the introduction of a polymerisable group, can be immobilised also by copolymerisation. With rhodium and iridium the immobilised ferrocenyl-diphosphine ligands form complexes that can be used as highly active catalysts in the enantioselective hydrogenation of carbon--carbon, carbon-nitrogen or carbon-oxygen double bonds. The selectivity and the total yield are surprisingly high for immobi
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Kovar et al., Organometallis in Chem. Syn. 1(1970/1971) 173-181.
Dohmann George R.
Kalinchak Stephen G.
Novartis AG
Shah Mukund J.
Sripada Pavanaram K.
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