Organic compounds -- part of the class 532-570 series – Organic compounds – Rare earth containing
Reexamination Certificate
2002-08-05
2004-12-21
Jones, Dameron L. (Department: 1616)
Organic compounds -- part of the class 532-570 series
Organic compounds
Rare earth containing
C526S906000, C526S915000, C528S088000, C502S100000, C523S400000
Reexamination Certificate
active
06833442
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a complex and an asymmetric catalyst using such a complex, and more particularly to an asymmetric catalyst high-enantioselectively promoting an epoxidation reaction of an amide or a ketone. Furthermore, the invention relates to a method for producing epoxides by using the asymmetric catalyst.
2. Description of Related Art
The epoxidation means a reaction for oxidatively changing an alkene to an epoxide by adding one oxygen atom to carbon-carbon double bond. As such an epoxidation method is known a method that the epoxidation is carried out in an inert organic solvent such as dichloromethane or the like by using an organic peracid as an epoxidizing agent.
There is recently known a method for synthesizing an optically active epoxide by catalytically oxidizing a prochiralic alkene with an asymmetric catalyst. This method using the asymmetric catalyst is a very important technique because it is possible to supply a great amount of an optically active compound from a tiny amount of the asymmetric catalyst.
Also, an epoxidation method using a cinnamate as a substrate of the catalyst.
However, an industrially mass-producible method is not known up to the present time. Furthermore, there are problems in the generality of the substrate. That is, only the cinnamate is known as the substrate of catalyst, so that there is a problem that the conventional catalyst used in the cinnamate can not be applied to a general substrate other than the cinnamate. Because, when the conventional catalyst is applied to a substrate containing a functional group such as carbon-carbon double bond, ketone or the like in its molecule, since such a catalyst is very high in the reactivity, a side reaction with such a functional group is caused and hence it is impossible to achieve an adequate epoxidation reaction.
Therefore, even if a compound containing a functional group such as carbon-carbon double bond, ketone or the like in its molecule is used as a substrate, it is desired to develop a method of producing an epoxide by using a catalyst capable of promoting the epoxidation reaction. If such a method is established, it is possible to simply synthesize an optically active compound useful for drug medicines in a large quantity. However, a convenient method for producing epoxide is no existence at this moment.
SUMMARY OF THE INVENTION
It is, therefore, an object of the invention to provide a general and multi-purpose method of producing an epoxide.
In order to achieve the above object, the inventors have made developments of asymmetric catalysts in the catalytic asymmetric epoxidation of unsaturated compounds and studies on the estimation of reactivity using calculation chemistry, and found out the following complexes and a method for producing an epoxide by using such a complex as a catalyst.
The complex according to the invention is characterized by representing the following general formula (I):
wherein X is P or As, and M is a rare earth metal, and R
1
is an alkoxy group or an alkyl peroxy group, and R
2
is a residue of a phenyl derivative, a residue of a heterocyclic compound or an alkyl group, and each of R
3
and R
4
is a substituent on an aromatic ring.
Also, the complex according to the invention is characterized by representing the following general formula (II):
wherein X is P or As, and M is a rare earth metal, and R
2
is a residue of a phenyl derivative, a residue of a heterocyclic compound or an alkyl group, and each of R
3
and R
4
is a substituent on an aromatic ring.
Furthermore, the complex according to the invention is characterized by representing the following general formula (III):
wherein X is P or As, and M is a rare earth metal, and R
2
is a residue of a phenyl derivative, a residue of a heterocyclic compound or an alkyl group, and each of R
3
and R
4
is a substituent on an aromatic ring.
In a preferable embodiment of the invention, M is at least one selected from the group consisting of La, Sm, Dy, Yb.
The asymmetric catalyst according to the invention is characterized by comprising the complex represented by the above general formula (I), (II) or (III).
The method for producing epoxide according to the invention is characterized by reacting an unsaturated amide or an unsaturated ketone with an oxidizing agent in the presence of the above asymmetric catalyst.
In a preferable embodiment of the method according to the invention, the unsaturated amide is an &agr;,&bgr;-unsaturated active amide having a nitrogen-containing heterocycle such as an imidazole derivative, an oxazolidinon or the like.
In another preferable embodiment of the method according to the invention, the unsaturated ketone is at least one selected from the group consisting of trans-&agr;,&bgr;-unsaturated ketones, cis-&agr;,&bgr;-unsaturated ketones, &agr;,&bgr;,&ggr;,&dgr;-unsaturated ketones.
In the other preferable embodiment of the method according to the invention, the oxidizing agent is at least one selected from the group consisting of t-butyl hydroperoxide (TBHP), cumene hydroperoxide (CMHP) and trityl hydroperoxide (TrOOH).
In a further preferable embodiment of the method according to the invention, the reaction is carried out in the presence of a coordinating solvent.
In a still further preferable embodiment of the method according to the invention, the coordinating solvent is selected from the group consisting of tetrahydrofuran (THF), dimethoxyethane and ether.
In a yet further preferable embodiment of the method according to the invention, the reaction is further carried out with an alcohol, a metallic amide, a reducing agent, a metallic enolate or the like to obtain an &agr;,&bgr;-epoxy ester, an &agr;,&bgr;-epoxy amide, an &agr;,&bgr;-epoxy aldehyde and &ggr;,&dgr;-epoxy-&bgr;-ketoester.
DETAILED DESCRIPTION OF THE INVENTION
The complex according to the invention is represented by the general formula (I):
wherein X is P or As, and M is a rare earth metal, and R
1
is an alkoxy group or an alkyl peroxy group, and R
2
is a residue of a phenyl derivative, a residue of a heterocyclic compound or an alkyl group, and each of R
3
and R
4
is a substituent on an aromatic ring.
Also, the complex according to the invention is represented by the general formula (II):
wherein X is P or As, and M is a rare earth metal, and R
2
is a residue of a phenyl derivative, a residue of a heterocyclic compound or an alkyl group, and each of R
3
and R
4
is a substituent on an aromatic ring.
Furthermore, the complex according to the invention is represented by the general formula (III):
wherein X is P or As, and M is a rare earth metal, and R
2
is a residue of a phenyl derivative, a residue of a heterocyclic compound or an alkyl group, and each of R
3
and R
4
is a substituent on an aromatic ring.
The inventors have focused attention on substrates other than cinnamate in view of the generality of the substrate. However, the conventionally used catalyst is very low in the functional group selectivity, so that it can not be applied to a substrate containing a functional group such as carbon-carbon double bond, ketone or the like.
Therefore, the inventors have attempted to develop various sorts of the catalyst for the epoxidation of unsaturated compounds and found out that the aforementioned complexes are effective as the catalyst.
In the above formulae (I)-(III), M is a rare earth metal. The rare earth metal is not particularly limited. As the rare earth metal, mention may be made of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Dy, Ho, Er and Yb. From a viewpoint of a higher enantioselectivity, at least one selected from the group consisting of La, Sm, Dy, Yb is preferable as the rare earth metal.
Also, each of R
3
and R
4
is a substituent on an aromatic ring and is not particularly limited. As the substituent, mention may be made of an alkyl group, an ether, a halogen atom, an amido group, an ester and so on.
The complex having a bone structure of the above formula (I), (II) or (III) can be synthesized as follows.
That is, the complex can be
Nemoto Tetsuhiro
Ohshima Takashi
Shibasaki Masakatsu
Jones Dameron L.
Oliff & Berridg,e PLC
The University of Tokyo
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