JPH0354650B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing α,β-unsaturated ketones, and more particularly to a method for producing α,β-unsaturated ketones by a novel reaction using allyl carbonate as a starting material. Unsaturated ketones such as cyclopentenone derivatives, cyclohexenone derivatives, cyclododecenone derivatives, etc. are useful chemical substances in the fields of perfumery, medicine, chemicals, etc. Recently, as a new method for synthesizing such unsaturated carbonyl compounds, allyl alkenyl esters of carbonic acid are combined with palladium and α,ω-alkylene di(disubstituted)
A method of treatment with a catalyst consisting essentially of phosphine has been reported (Tetrahedron Letters, Vol. 24, No. 17, Nos. 1797-1800, published in 1983). According to this report, specific bidentate ligands constituting the catalyst are essential for the reaction, and when using a general-purpose ligand such as triphenylphosphine, It is described that the selectivity is poor. Therefore, in such conventional techniques, usable ligands are limited to expensive compounds with special structures, and the catalyst activity, reaction selectivity, and stability of the catalyst within the reaction system are not always satisfactory. I couldn't say it was possible. Therefore, the present inventors conducted intensive studies to improve the drawbacks of the prior art, and found that this reaction does not necessarily require α,ω-alkylene di(disubstituted) phosphine, which was considered to be an essential catalyst component in the above report. It is important to note that even monodentate ligands such as triphenylphosphine are effective when used within a specific range, and that the activity and stability of the catalyst are further improved when the reaction is carried out in the presence of specific compounds. The inventors have discovered that the present invention has been completed. Thus, according to the present invention, α,β- represented by the following general formula [] is produced by contacting diethyl carbonate represented by the following general formula [] with a palladium compound catalyst in the presence of an allyl compound.
A method of making an unsaturated carbonyl compound is provided. (In the above formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ represent hydrogen or hydrocarbon residues, and R ₁ ,
R ₂ , R ₃ and R ₄ may be chain-like or each may form a ring in any combination. ) In the present invention, an allyl type carbonate ester represented by the above general formula [] is used as a starting material. In the formula, R ₁ is not only a hydrogen atom but also a methyl group,
Refers to an alkyl group such as an ethyl group, a propyl group, a pentyl group, or an alkylene group that is bonded with R ₂ , R ₃ or R ₄ to form a ring such as a cyclopentane ring, a cyclohexane ring, a cyclododecane ring, etc. , R ₂ , R ₃ and R ₄ mean a hydrogen atom or an alkyl group or alkylene group similar to R ₁ , and R ₅ , R ₆ , R ₇ and R ₈ mean hydrogen or an alkyl group. Among the above substituents, R ₁ , R ₂ , R ₃ and
R ₄ may form a ring in any combination. Specific examples of such compounds include allyl carbonate (1-cyclohexenyl) ester, allyl carbonate (1-cyclopentenyl) ester, allyl carbonate (2-methyl-1-cyclohexenyl) ester, and allyl carbonate (6-methyl) ester. -1-Cyclohexenyl ester, allyl carbonate (1-cyclododecenyl) ester, allyl carbonate (cyclohexylidene) ester, crotyl carbonate (1-cyclohexenyl) ester, -2-pentenyl carbonate (1-
cyclohexenyl) ester, allyl carbonate (2-
propyl-1-cyclohexenyl) ester, allyl carbonate (2-pentyl-1-cyclohexenyl) ester, allyl carbonate (2-pentyl-1-
cyclopentenyl) ester, allyl carbonate (2-
pentenyl-1-cyclopentenyl) ester,
Allyl carbonate (2-pentynyl-1-cyclopentenyl) ester, allyl carbonate (1-propenyl)
Examples include ester, allyl carbonate (1-hexenyl) ester, allyl carbonate (2-methyl-1-butenyl) ester, and allyl carbonate (3-methyl-1-butenyl) ester. These compounds can be synthesized according to conventional methods, for example, allyl carbonate (1-cyclohexenyl)
Taking ester as an example, it can be easily synthesized by a method of reacting cyclohexanone and allyl chloroformate. In the present invention, a palladium compound catalyst is used in the reaction. Here, the palladium compound catalyst refers to a palladium compound itself or one consisting of a palladium compound and a ligand. The palladium compound used is a palladium salt or complex, and specific examples include tris(dibenzylideneacetone) dipalladium, tris(tribenzylideneacetylacetone) tripalladium, palladium acetate, palladium propionate, palladium butyrate. , palladium benzoate, palladium acetylacetonate, palladium nitrate, palladium sulfate, palladium chloride,
Examples include. When using a strong inorganic acid salt among these compounds, it is desirable to coexist a base such as potassium acetate, sodium alcoholate, or tertiary amine. Among palladium compounds, it is preferable to use zero-valent olefin complexes or divalent organic compounds. The ligand used is a monodentate or polydentate electron-donating compound having a group element of the periodic table, that is, nitrogen, phosphorus, arsenic, or antimony, as a coordination atom, and specific examples thereof include pyridine, quinoline, trimethylamine, Nitrogen-containing compounds such as triethylamine, tributylamine, α, α′-dipyridine, 110-phenanthroline, N,N,N′,N′-tetramethylethylenediamine; triethylphosphine, tri-n-butylphosphine,
Tri-n-dodecylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-
p-biphenylphosphine, tri-o-methoxyphenyl-phosphine, phenyldiphenoxyphosphine, triethylphosphite, tri-n-
Butyl phosphite, tri-n-hexyl phosphite, triphenyl phosphite, tri-o-
Phosphorus-containing compounds such as tolylphosphite, triphenylthiophosphite, α,β-ethylenedi(diphenyl)phosphine, α,β-ethylenedi(dibutyl)phosphine, α,γ-propylenedi(diphenyl)phosphine; triethylarsenic, Examples include arsenic-containing compounds such as tributyl arsenic and triphenyl arsenic; and antimony-containing compounds such as tripropylantimony and triphenyl antimony. Among them, nitrogen-containing compounds and phosphorus-containing compounds are preferred in terms of reaction activity, selectivity, economic efficiency, and the like. Although such a ligand is not necessarily essential as a catalyst component, by using an appropriate amount, the stability of the catalyst can be greatly improved. The amount of the ligand used is not necessarily constant depending on the type, but in the case of monodentate ligands, it is usually 2 mol or less per mol of the metal compound, preferably 0.1 to 1.5 mol.
In the case of a bidentate ligand, the amount is usually 1.5 mol or less, preferably 0.1 to 1.2 mol. The amount of the catalyst to be used in the present invention is appropriately selected, but it is usually used in a ratio such that the palladium compound is usually 0.01 to 10 moles, preferably 0.1 to 5 moles, per 100 moles of the raw material. Although the palladium compound and the ligand may be reacted in advance, the catalyst is usually prepared by bringing both components into contact in a reaction system. The reaction of the present invention proceeds according to the following reaction formula by bringing the starting material into contact with a catalyst in the presence of an allyl compound. The reaction temperature is usually 20°C or higher, preferably 50 to 150°C, and the reaction time is usually 5 minutes to
It is 10 hours. The allyl compound used is an ester or ether having at least one allyl type residue in the molecule, and specific examples include allyl acetate, methallyl acetate, crotyl acetate, 2-pentenyl acetate, cinnamyl acetate, allyl propionate,
Allyl acetate, allyl benzoate, diallyl carbonate, diallyl oxalate, diallyl malonate, diallyl succinate, diallyl adipate, diallyl phthalate, methyl allyl ether, methyl methallyl ether, methyl crotyl ether, ethyl allyl ether, propyl allyl ether, Examples include butyl allyl ether, diallyl ether, and phenyl allyl ether, among which compounds having 10 or less carbon atoms are preferred. The proportion of allyl compounds to be used is selected as appropriate;
Usually 0.5 mol or more per mol of palladium compound,
Preferably it is 0.7 to 2 mol. The method of adding the allyl compound is not particularly limited, and examples thereof include a method of adding it at the catalyst preparation stage, a method of adding it at the time of starting the reaction, a method of adding it during the progress of the reaction, etc. If necessary, it can be added in two or more portions. Among these, the method of adding from the catalyst preparation stage is preferred. Further, a diluent can be present during the reaction, and specific examples thereof include acetonitrile,
Nitrilic acids such as propionitrile, butyronitrile, benzonitrile, etc. Amides such as dimethylformamide, diethylformamide, dimethylacetamide, dimethylpropioamide, N-methylpyrrolidone, etc.; Tetrahydrofuran, dioxane, diptyl ether, ethylene glycol dimethyl ether, etc. Ethers such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; Esters such as methyl acetate, ethyl acetate, propyl acetate, ethyl propionate, etc.; ethanol, propanol, ter-butanol, ethylene glycol, diethylene glycol mono Alcohols such as ethyl ether;
Examples include sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide; hydrocarbons such as n-hexane, cyclohexane, benzene, toluene, xylene, etc. Among them, aprotic polar solvents, especially nitriles, amides, and ethers. , ketones, and esters. These diluents typically have a starting material concentration of 1 to
It is used in a proportion of 50% by weight, and its use can improve reaction activity, selectivity, and catalyst stability. Although other reaction conditions can be selected as appropriate, the reaction temperature is usually 20°C or higher, preferably 50 to 150°C, and the reaction time is usually 5 minutes to 10 hours. After the reaction is complete, a highly purified α,β-unsaturated carbonyl compound, i.e., α,β-unsaturated ketone or α,β-unsaturated aldehyde, is obtained by separating the target product from the reaction solution using a conventional method. can get. Such unsaturated carbonyl compounds are used as intermediates for the synthesis of various useful compounds, particularly for perfumes, medicines, and the like. Thus, according to the present invention, it is possible to improve the stability of the catalyst in the reaction system compared to the conventional method, and to obtain the target α, with high activity and selectivity.
β-unsaturated carbonyl compounds can be produced. The present invention will be explained in more detail with reference to Examples below. In addition, regarding the stability of the catalyst in the examples, the occurrence of precipitation of palladium in the reaction system was observed, and those that did not generate precipitation even after 12 hours after the completion of the reaction were designated as A. Let E be the one where .
Evaluated in stages. Example 1 Allyl (2-methyl-1-cyclohexenyl) carbonate ester in a container

[Formula] 20 mol of acetonitrile per 1 mol, palladium acetate
0.003 mol of triphenylphosphine, 0.003 mol of diallyl carbonate, and 0.003 mol of diallyl carbonate. After stirring rapidly at room temperature, the temperature was raised to the boiling point of the solvent, and the reaction was carried out under reflux under an argon atmosphere for 3 hours. After the reaction was completed, the product was distilled under reduced pressure according to a conventional method. As a result, 2-methyl-2-cyclohexene-1
-one (hereinafter referred to as MCH) was obtained with a yield of 98%. The identification of these compounds was performed using IR,
This was done by using NMR and mass spectra. Moreover, the stability of the catalyst was A. Example 2 An experiment was conducted in the same manner as in Example 1 except that the type of allyl compound was changed to the compounds shown in Table 1. The results are shown in Table 1.

[Table] Example 3 A reaction was carried out in the same manner as in Example 1 except that 0.003 mol of the compound shown in Table 2 was used as a ligand. The results are shown in Table 2.

[Table] Example 4 A reaction was carried out in the same manner as in Example 1 except that the compounds shown in Table 3 were used as starting materials. The results are shown in Table 3.

[Table] Example 5 A reaction was carried out according to Example 1 except that palladium acetylacetonate was used in place of palladium acetate, and almost the same results as in Example 1 were obtained. Example 6 A reaction was carried out according to Example 1 except that tris(dibenzylideneacetone)dipalladium was used instead of palladium acetate.
Almost the same results were obtained.

Claims (1)

[Claims] 1. General formula [] (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and
R ₈ represents a hydrogen atom or a hydrocarbon residue, R ₁ ,
(R ₂ , R ₃ and R ₄ may be chain-like or each may form a ring in any combination) and contact the carbonic acid diester represented by R 2 , R 3 and R 4 with a palladium compound catalyst in the presence of an allyl compound. A general formula characterized by [] A method for producing an α,β-unsaturated carbonyl compound represented by the formula (wherein R ₁ , R ₂ , R ₃ and R ₄ are the same as above).