Plant protecting and regulating compositions – Plant growth regulating compositions – Organic active compound containing
Reexamination Certificate
2002-09-03
2004-03-30
Lambkin, Deborah C. (Department: 1626)
Plant protecting and regulating compositions
Plant growth regulating compositions
Organic active compound containing
C549S265000, C549S299000
Reexamination Certificate
active
06713435
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing optically active lactone compounds. More specifically, the invention relates to a method for producing optically active lactone compounds by Baeyer-Villiger oxidation of cyclic ketone compounds using salen cobalt complexes possessing a cis-&bgr; structure as a catalyst. Such optically active lactone compounds can be used for the synthesis of medicines and agrochemicals. Further, both S isomers and R isomers can be synthesized by choosing the catalyst.
2. Related Art Statement
Asymmetric Baeyer-Villiger oxidation is an important reaction in the organic synthetic chemistry. Still, these is no general method for achieving sufficient enantioselectivity in the oxidation. Baeyer-Villiger oxidation starts with nucleophilic attach of an oxidant to a carboxyl group, followed by the migration of the carbonyl-substitutent (R3 or R4) to the vicinal oxygen atom to give a lactone (or esters). Lewis acid accelerates both the nuclceophic addition and the migration through its coordination to the carbonyl group and the leaving group (X′), respectively. The reaction formula is shown below.
Bolm and co-workers reported enantiomer-differentiating Bayer-Villiger oxidation of racemic 2-substituted cycloalkanones using a combination of molecular oxygen and aldehyde (Mukaiyama condition) in the presence of bis(oxazolinyl-phenolato)copper (II) complex as a catalyst (Bolm C., Schlingloff G. and Weichhardt K., Angew. Chem. Int. Ed. Engl. 1994, 33, 1848-1849). Enantioselective Baeyer-Villiger oxidation using chiral platinum complexes as catalysts were also reported (Gusso A., Baccin C., Pinna F., and Strukul G., Organometallics, 1994, 13, 3442-3451). Thereafter, asymmetric Baeyer-Villiger oxidations using various optically active metal complexes as catalysts have been investigated, and high enatioselectivity has been realized for the reactions of some specific substrates.
However, the maximum enantioselectivity in the reported asymmetric Baeyer-Villiger oxidation of prochiral ketones, particularly, prochiral 3-substituted cyclobutanone compounds by using optically active metal complexes as catalyst was 47%ee (until August, 2001) (Lopp M., Paju A., Kanger T., and Pehk T., Tetrahedron Lett., 1996, 37, 7583-7586, Bolm C., Schlingloff G., and Bienewald E, J. Mol. Cat. A; Chem., 1997, 117, 347-350, Bolm C., and Beckmann O., Chirality, 2000, 12, 523-525, Shinohara T., Fujioka S., and Kotsuki, H., Heterocycles, 2001, 55, 237-241).
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a method for producing lactone compounds at an optically high purity by asymmetric Baeyer-Villiger oxidation of prochiral ketones.
Having made strenuous investigations to solve the above-mentioned problems, the inventors discovered that lactone compounds of optically high purities could be produced by the Baeyer-Villiger oxidation of cyclic ketone compounds with specific oxidants in the presence of cobalt(salen) complexes of cis-&bgr; structure as catalyst. The present invention was accomplished based on this discovery.
(1) That is, the present invention relates to a method for producing an optically active lactone compound by Baeyer-Villiger oxidation of a cyclic ketone compound with at least one kind of oxidants selected from the group consisting of hydrogen peroxide and urine-hydrogen peroxide adduct (UHP) in the presence of a cobalt(salen) complex possessing cis-&bgr; structure expressed by the following formula (I) or (II) as a catalyst.
in which X and Y independently denote H, t-butyl group or an electron-withdrawing substituting group and W is a halogen element.
in which X and Y independently denote H, t-butyl group or an electron-withdrawing group and Z
−
is a monovalent non-coordinating anion.
The followings are preferred embodiments of the lactone-producing method of the present invention.
(2) X and Y in the cobalt(salen) complex of the formula (I) independently denote t-butyl group, F, Cl, Br, I or a nitro group.
(3) X and Y in the cobalt(salen) complex of the formula (I) denote t-butyl group and nitro group, respectively.
(4) W in the cobalt(salen) complex of the formula (I) denotes iodine.
(5) X and Y in the cobalt(salen) complex of the formula (II) independently denote F, Cl, Br or I.
(6) X and Y in the cobalt(salen) complex of the formula (II) denote F.
(7) Z
−
in the cobalt(salen) complex of the formula (II) denotes non-coordinating anion such as SbF
6
−
.
(8) The cyclic ketone compound is represented by any one of the following formulae (III), (IV) and (V).
in which R
1
is a substituted or non-substituted C1-C20 alkyl group or a substituted or non-substituted C6-C15 aryl group.
in which R
2
is a substituted or non-substituted C1-C20 alkyl group or a substituted or non-substituted C6-C15 aryl group.
(9) The cyclic ketone compound is represented by the formula (III).
(10) The cyclic ketone compound is 3-phenylcyclobutanone, 3-(p-chlorophenyl)cyclobutanone, 3-(p-methoxyphenyl)cyclobutanone or 3-octyl cyclobutanone.
(11) The cyclic ketone compound is represented by the formula (V).
(12) The lactone compound is represented by any one of the following formulae (VI), (VII) and (VIII).
in which R
1
is a substituted or non-substituted C1-C20 alkyl group or a substituted or on-substituted C6-C15 aryl group.
in which R
2
is a substituted or non-substituted C1-C20 alkyl group or a substituted or non-substituted C6-C15 aryl group.
(13) The lactone compound is represented by the formula (VI).
(14) The lactone compound is &bgr;-phenyl-&ggr;-butylolactone, &bgr;-(p-chlorophenyl)-&ggr;-butylolactone, &bgr;-(p-methoxyphenyl)-&ggr;-butylolactone or &bgr;-octyl-&ggr;-butylolactone.
(15) The lactone compound is represented by the formula (VIII).
(16) The lactone compound has an optical purity of not less than 47% ee.
(17) The lactone compound-producing method further uses at least one kind of polar solvents.
(18) The polar solvent is any one selected from acetonitrile, ethyl acetate, diethyl ether, tetrahydrofuran (THF) and a C1-C3 alcohol.
(19) The Baeyer-Villiger oxidation is effected in a temperature range of −20° C. to 25° C.
Any combinations of (2) to (19) are also preferred embodiments of the lactone-producing method according to the present invention, so long as no discrepancy occurs.
The present invention also relates to a catalyst to be used in the above-mentioned methods, that is,
(20) the invention relates to a cobalt(salen) complex having a cis-&bgr; structure represented by the following formula (I) or (II).
in which in which X and Y independently denote H, t-butyl group or an electron-withdrawing group and W is a halogen element.
in which X and Y independently denote H, t-butyl group or an electron-withdrawing group and Z
−
is a monovalent non-coordinating anion.
The followings are preferred embodiments of the complexes of the present invention.
(21) X and Y in the cobalt(salen) complex of the formula (I) independently denote t-butyl group, F, Cl, Br, I or nitro group.
(22) X and Y in the cobalt(salen) complex of the formula (I) denote t-butyl group and nitro group, respectively.
(23) W in the cobalt(salen) complex of the formula (I) denotes iodine.
(24) X and Y in the cobalt(salen) complex of the formula (II) independently denote F, Cl, Br or I.
(25) X and Y in the cobalt(salen) complex of the formula (II) denote F.
(25) Z
−
in the cobalt(salen) complex of the formula (II) denotes non-coordinating anion such as SbF
6
−
.
Any combinations of (21) to (26) are also preferred embodiments of the catalyst of the present invention, so long as no discrepancy occurs.
These and other objects, features and advantages of the invention will be apparent from reading of the following detailed description of the invention when taken with the understanding that some variations, changes or variations could be easily made by the skilled person in the art to which the invention pertains.
DETAILED DESCRIPTION OF THE INVENTION
In the
Ito Katsuji
Katsuki Tsutomu
Uchida Tatsuya
Burns Doane , Swecker, Mathis LLP
Kyushu University
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