Heteroarylic-arylic diphosphines as chiral ligands

Details Heteroarylic-arylic diphosphines as chiral ligands Heteroarylic-arylic diphosphines as chiral ligands

1999-04-18

2000-11-28

Lambkin, Deborah C.

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

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

548412, 549 6, 549216, C07F 928, C07F 902, C07D33700

Patent

active

061537586

DESCRIPTION:

BRIEF SUMMARY
OBJECT OF THE INVENTION

The present invention relates to chiral diphosphines of a mixed heteroarylic-arylic type, the use of said diphosphines as ligands for transition metals, and complexes between said diphosphines and said transition metals.
The present invention also relates to the use of said complexes as chiral catalysts for stereocontrolled (stereoselective) reactions, such as for instance diastereo- and enantioselective reduction reactions, or asymmetric isomerisation reactions, hydroformylation reactions, hydrocyanation reactions as well as other reactions of carbon--carbon bond formation.
The present invention further relates to a process for the preparation of said chiral diphosphines of a mixed heteroarylic-arylic type, as well as to a process for the preparation of said complexes between said diphosphines and said transition metals.
Moreover, the present invention also relates to stereoselective reactions, such as for instance diastereo- and enenatioselective reductions, realised by using said chiral catalysts.


STATE OF THE ART

As is known, stereoselective reactions, and in particular stereocontrolled reductions such as for instance diastereo- and enantioselective hydrogenation reactions, are of great importance and have been studied for many years. Such reactions lead directly to the formation of optically active compounds which would be otherwise obtainable only as racemes to be submitted to resolution in the individual enatiomers according to conventional techniques. In these cases, there takes place a simultaneous formation of identical quantities of the undesired enantiomer which must be, removed and/or reconverted. The realisation of stereoselective reactions has allowed to eliminate most of the aforementioned problems, opening therefore a research field of great interest.
Generally, stereocontrolled reactions realised, for instance, by means of chiral catalysts, allow to obtain optically active reaction products, often with good enantiomeric excesses. Chiral catalysts of a known type utilised in this field, and particularly for stereocontrolled reduction reactions, are for instance constituted by complexes between transition metals and chiral phosphines such as DIPAMP [KNOWLES W. S. et al., J.Chem.Soc. chem. Commun. 10 (1972); VINEYARD B. D. et al., J.Am.Chem.Soc. 99, 5946(1977)] or CHIRAPHOS [FRYZUK M. D. et al., J.Am.Chem.Soc. 99, 6562(1977)]. Other examples of chiral phosphines include for intance BINAP, BIPHEMP, BICHEP [NOYORI T. et al., J.Am.Chem.Soc. 102, 7932(1980); SCHMID R. et al., Helv.Chim.Acta 71, 897(1988); MIYASHITA A. et al., Chem.Lett. 1849(1989)]. The latter are phosphines whose chirality is due to the presence of an atropoisomeric diaryl system (C.sub.2 symmetry system), and they have been utilised for the preparation of very efficient chiral systems; however, the phosphine synthesis process is rather complex and comprises many complicated steps, and accordingly the corresponding chiral catalysts are very expensive.
There are also described [WO 96/01831, by the same Applicant] chiral diphosphines constituted by a biheterocyclic 5-atom aromatic system (C.sub.2 symmetry atropoisomeric system) which, by complexation with transition metals, form very efficient chiral catalysts); the aforesaid diposphines are prepared according to synthesis processes simpler compared with those utilised for BINAP, BIPHEMP and BICHEP, and consequently the corresponding chiral catalysts are less expensive. In spite of this, the synthesis processes of the aforesaid chiral diphosphines of a diheterocyclic type are still rather complicated, as they require many steps; besides, the above processes only allow to prepare chiral phosphines wherein the two phosphorous atoms carry substituents that are always equal to one another.
There are also known chiral catalysts constituted by complexes between C.sub.1 symmetry phosphine systems and transition metals; these catalysts, while being generally less expensive, are also often less efficient than the corresponding C.sub.2 symmetry catalysts, as dif

REFERENCES:
patent: 5739396 (1998-04-01), Trost et al.
patent: 5907045 (1999-05-01), Antognazza et al.

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