Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-02-09
2003-03-18
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C548S402000, C548S433000, C548S533000, C556S011000, C556S012000, C556S018000, C556S022000, C556S033000, C556S034000, C556S040000, C560S128000, C560S190000, C560S203000, C568S715000, C568S881000, C568S886000, C502S154000, C502S162000, C502S165000, C502S166000
Reexamination Certificate
active
06534657
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to novel chiral ligands derived from ferrocenes and catalysts prepared therefrom for applications in asymmetric catalysis. More particularly, the present invention relates to transition metal complexes of these chiral phosphine ligands. The transition metal complexes according to the present invention are useful as catalysts in asymmetric reactions, such as, hydrogenation, hydride transfer, allylic alkylation, hydrosilylation, hydroboration, hydrovinylation, hydroformylation, olefin metathesis, hydrocarboxylation, isomerization, cyclopropanation, Diels-Alder reaction, Heck reaction, isomerization, Aldol reaction, Michael addition; epoxidation, kinetic resolution and [m+n] cycloaddition.
2. Description of the Prior Art
Molecular chirality plays an important role in science and technology. The biological activities of many pharmaceuticals, fragrances, food additives and agrochemicals are often associated with their absolute molecular configuration. A growing demand in pharmaceutical and fine chemical industries is to develop cost-effective processes for the manufacture of single-enantiomeric products. To meet this challenge, chemists have explored many approaches for acquiring enantiomerically pure compounds ranging from optical resolution and structural modification of naturally occurring chiral substances to asymmetric catalysis using synthetic chiral catalysts and enzymes. Among these methods, asymmetric catalysis is perhaps the most efficient because a small amount of a chiral catalyst can be used to produce a large quantity of a chiral target molecule [Book, Ojima, I., Ed.
Catalytic Asymmetric Synthesis,
VCH, New York, 1993 and Noyori, R.
Asymmetric Catalysis In Organic Synthesis,
John Wiley & Sons, Inc., New York, 1994].
Asymmetric hydrogenation accounts for major part of all asymmetric synthesis on a commercial scale. Some dramatic examples of industrial applications of asymmetric synthesis include Monsanto's L-DOPA synthesis (asymmetric hydrogenation of a dehydroamino acid, 94% ee, 20,000 turnovers with a Rh-DIPAMP complex) [Knowles, W. S.
Acc. Chem. Res.
1983, 16, 106], Takasago's L-menthol synthesis (asymmetric isomerization, 98% ee, 300,000 turnovers with a Rh-BINAP complex) [Noyori, R.; Takaya, H.
Acc. Chem. Res.
1990, 23, 345] and Norvatis' (S)-Metolachlor synthesis (asymmetric hydrogenation of an imine, 80% ee, 1,000,000 turnovers with an Ir-ferrocenyl phosphine complex) [Spindler, F.; Pugin, B.; Jalett, H.-P., Buser, H.-P.; Pittelkow, U.; Blaser, H,-U., Altanta, 1996; Chem. Ind. (Dekker), 1996, 63 and Tongni, A.
Angew. Chem.. Int. Ed Engl.
1996, 356, 14575].
Invention of chiral ligands for transition metal-catalyzed reactions plays a critical role in asymmetric catalysis. Not only the enantioselectivity depends on the framework of chiral ligands, reactivities can often be altered by changing the steric and electronic structure of the ligands. Since small changes in the ligand can influence the (delta)(delta)G of the rate-determining step, it is very hard to predict which ligand can be effective for any particular reaction or substrate. Development of new structural motifs is important in the process of ligand development.
Several important chiral phosphines have been studied during 30 years. Knowles' DIPAMP [Knowles, W. S.; Sabacky, M. J.; Vineyard, B. D.
J. Chem. Soc., Chem. Commun.
1972, 10] and Kagan's DIOP [Kagan, H. B.; Dang, T.-P.
J. Am. Chem. Soc.
1972, 94, 6429] ligands were reported for Rh (I)-catalyzed asymmetric hydrogenation at about the same time. The great success in asymmetric hydrogenation of dehydroamino acids has stimulated continuing research on new chiral phosphine ligands. Various bidentate chiral diphosphines such as Chiraphos (Bosnich)[Fryzuk, M. D.; Bosnich, B.
J. Am. Chem. Soc.
1977, 99, 6262], BPPM (Achiwa, Ojima) [(a) Achiwa, K.
J. Am. Chem. Soc.
1976, 98, 8265. (b) Ojima, I.; Yoda, N.
Tetrahedron Lett.
1980, 21, 1051], DegPhos (Nagel)[Nagel, U.; Kinzel, E.; Andrade, J.; Prescher, G.
Chem. Ber.
1986, 119, 3326] and ferrocenyl chiral phosphines (Hayashi, Kumada, Ito)[Hayashi, T.; Kumada, M. Acc. Chem. Res., 1982, 15, 395] were discovered. Two excellent ligands come out of extensive ligand studies; BINAP (Otsuka, Nayori and Takayi)[Miyashita, A.; Yasuda, A.; Takaya, H.; Toriumi, K.; Ito, T.; Souchi, T.; Noyori, R.
J. Am. Chem. Soc.
1980,102,7932. Miyashita, A.; Takaya, H.; Souchi, T.; Noyori, R.
Tetrahedron
1984, 40, 1245.] in the early 80's is one of the most frequently used bidentate chiral phosphines, and DuPhos (Burk)[Burk, M. J.; Feaster, J. E.; Nugent, W. A.; Harlow, R. L.
J. Am. Chem. Soc.
1993, 115, 10125] in the early 90's has also shown impressive enantioselectivities. The Rh, Ru and Ir complexes of these ligands have been used as catalysts for asymmetric hydrogenations of olefins, ketones and imines. These ligands are also useful for other asymmetric reactions such as isomerization, hydroacylation, the Heck reaction, and the Grignard coupling reaction. However, there are still a variety of reactions in which only modest enantioselectivity has been achieved with these ligands, and substrate scope is limited both for hydrogenation and for other reactions. Complementary classes of chiral ligands are needed. Due to the critical role of chiral ligands in reaction activity and selectivity, many new phosphine ligands were invented. The major feature of the new chiral phosphine ligands is their structural diversity where different structural motif is created, ligand complexity increases, and the steric and electronic properties of ligands are more tunable. Some of these ligands include monodentate chiral phosphines (MOP, Hayashi) [Uozumi, Y.; Hayashi, T.
J. Am. Chem. Soc.
1991, 113, 9887], ferrocenyl phosphine bearing two different phosphine groups (Togni)[Togni, A.
Angew. Chem. Int. Ed. Engl.
1996, 356, 14575], Trost's chiral bisphosphines [Trost, B. M.; Van Vranken, D. L.
Chem. Rev.
1996, 96, 395], mixed N-P ligands [Pfaltz, A.
Acc. Chem. Res.
1993, 26, 339], Trans diphosphines (TRAP, Ito) [Sawamura, M.; Kuwano, R.; Ito, Y.
Angew. Chem. Int. Ed.Engl.
1994, 33, 111] and phosphinite ligand (BINAPHOS, Takaya) [Sakai, N.; Mano, S.; Nozaki, K.; Takaya, H.
J. Am. Chem. Soc.
1993, 115,7033]. These new ligands are effective for several asymmetric reactions: hydrosilylation, hydrogenation of imines, allylic alkylation, Michael addition and hydroformylation.
Although there are few chiral ferrocene phosphines reported in the literature (TRAP, Togni's ligands and Hayashi's ligands), lack of systematic studies hinders the broad utilities of chiral ferrocene phosphines for asymmetric catalytic reactions. Some of the advantages of chiral phosphines containing ferrocene backbone include the following:
1) ferrocene phosphines are generally quite stable in air and are in a solid form;
2) phosphines adjacent to a ferrocene group are electron-donating, which can aid certain catalytic reactions; and
3) chiral ferrocene phosphines can be easily generated through enantioselective deprotonation of a C—H group in the ferrocene, asymmetric reduction of ferrocene alkyl ketones or resolution methods.
The present invention includes new inventive structures derived from ferrocene s. The new ligands have been demonstrated to be effective for a range of asymmetric catalytic reactions, especially asymmetric Pd-catalyzed allylic alkylation and Ag-catalyzed [3+2] cyclization of azomethine ylides.
SUMMARY OF THE INVENTION
In broad concept, the present invention includes ferrocene anchored chiral ligands and metal complexes based on such chiral ligands useful in asymmetric catalysis. Accordingly, the present invention includes a ligand selected from the group consisting of compounds represent
Nazario-Gonzalez Porfirio
Ohlandt Greeley Ruggiero & Perle L.L.P.
The Penn State Research Foundation
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