JP3367057B2 - Process for producing 4-tert-butyldioxy-2,5-cyclohexadien-1-ones - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing 4-tert-butyldioxy-2,5-cyclohexadien-1-ones. [0002] General formula 1 (Wherein, R represents an alkyl group or a phenyl group which may be substituted, R ¹ , R ² , R ³ and R ⁴ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) R and R ¹ may be bonded to each other to form a ring.) 4-t-butyldioxy-2
5-Cyclohexadien-1-ones are obtained from Diels-
It is useful as a synthetic intermediate such as a dienophile in an Alder reaction or an acceptor in a Michael reaction. Conventionally, as a method for producing such 4-t-butyldioxy-2,5-cyclohexadien-1-ones, phenols and t-butylhydroperoxide are reacted in the presence of pyridinium dichromate (PDC). Method (Tetrahedron Lett.Vol.29 (1988) 3907-39
10], a method using PDC or chromium oxide (CrO ₃ ) as a catalyst [J. Chem. Res. (S) 1990, p. 96] is known. [0004] However, the former method has a problem of environmental pollution because a toxic chromium compound is used in a stoichiometric amount, and the latter method has a problem of using a chromium compound. Not only does the same problem occur,
The yield of the target compound was as low as about 30%, and none of these methods was industrially advantageous. [0005] From these facts, the inventors of the present invention did not use a highly toxic catalyst such as a chromium compound, and were able to produce 4-t-butyldioxy-2,5 represented by the general formula 1 in good yield. As a result of studying a method for producing 1-cyclohexadiene-1-ones, the present invention has been achieved. [0006] That is, the present invention provides a compound represented by the following general formula: (Wherein R and R ^{1 to} R ⁴ have the same meanings as described above) in the presence of a ruthenium catalyst in the presence of t
And a method for producing 4-tert-butyldioxy-2,5-cyclohexadien-1-one represented by the above general formula (1), characterized by reacting with 4-butyl hydroperoxide. In the present invention, the phenols represented by the above general formula 2 used as raw materials include, for example, p-cresol, p-ethylphenol, p-isopropylphenol, p-hexylphenol, p-phenylphenol, 4,6-di-t-butylphenol,
2,4,6-trimethylphenol, 2,6-di-t-
Butyl-4-methylphenol, 5,6,7,8-tetrahydro-2-naphthol, 5-indanol and the like. In this reaction, the choice of the catalyst is extremely important, and in the present invention, Ru ₃ (CO) ₁₂ , RuCl
₂ (PPh ₃ ) ₃ , RuCl ₂ (bpy) ₂ , RuCl ₃ .nH
Ruthenium catalysts such as ₂ O, Ru (OAc) ₃ , Ru (acac) ₃ are used. Such ruthenium catalysts may be used by mixing them, or these catalysts may be used by being supported on a heteropolyacid, silica gel, carbon powder, a polymer substance, or the like. In the reaction of the phenols with t-butyl hydroperoxide, the amount of t-butyl hydroperoxide used is usually 1 to 10 moles, preferably 2 to 6 moles, relative to the phenols. . The amount of the ruthenium catalyst used is usually 0.01 to 50 mol%, preferably 0.1 to 10 mol%, based on phenols.
Range. The reaction is usually carried out in a solvent. Examples of the solvent include halogenated hydrocarbons such as dichloromethane, chloroform and ethylene dichloride, esters such as ethyl acetate, nitriles such as acetonitrile, benzene, toluene, xylene and monochlorobenzene. And aromatic ketones such as acetone and methyl ethyl ketone. The use amount thereof is not particularly limited, but is usually 1 to 20 times by weight of phenols. The reaction temperature is usually in the range of 0 ° C. to the reflux temperature of the reaction system, but is preferably in the range of 10 to 50 ° C. The reaction time is not particularly limited, and the reaction mixture is analyzed by LC or the like, and the point at which the production rate of the desired 4-t-butyldioxy-2,5-cyclohexadien-1-one does not increase is defined as the reaction end point. do it. After completion of the reaction, the reaction mixture is purified by, for example, florisil column chromatography and concentrated, whereby the desired 4-tert-butyldioxy-2,5-cyclohexadien-1-one can be obtained. The 4-t-butyldioxy-2,5-cyclohexadien-1-ones thus produced include 4-t-butyldioxy-4-methyl-2,5-cyclohexadien-1-one, 4-t-butyldioxy-1-one. Butyldioxy-4-ethyl-2,5-cyclohexadien-1-one, 4-tert-butyldioxy-4-isopropyl-2,
5-cyclohexadien-1-one, 4-tert-butyldioxy-4-hexyl-2,5-cyclohexadien-1-one, 4-tert-butyldioxy-4-phenyl-2,5-cyclohexadien-1-one, 4-t- Butyldioxy-4,6-di-tert-butyl-2,5-cyclohexadien-1-one, 4-tert-butyldioxy-2,4,6-trimethyl-2,5-cyclohexadien-1-one, 4-tert-butyldioxy-2 , 6-t
-Butyl-4-methyl-2,5-cyclohexadien-1-one, 1-tert-butyldioxybicyclo [4.4.
0] decal 2,5-dien-4-one, 1-tert-butyldioxybicyclo [4.3.0] noner 2,5-dien-4-one and the like. According to the method of the present invention, 4-t-butyldioxy-2,2 is obtained in good yield without causing toxicity problems.
5-cyclohexadien-1-ones can be produced. EXAMPLES The present invention will be described below with reference to examples, but it goes without saying that the present invention is not limited to these examples. Example 1 0.652 g of p-cresol, RuCl ₂ (PPh ₃ )
_{3 To} a mixture of 0.173 g and 6 ml of anhydrous benzene,
Under an argon atmosphere, 7.3 ml of a 3.3 molar concentration of t-butyl hydroperoxide in benzene was added dropwise over 2 hours at room temperature, and the mixture was further stirred at the same temperature for 3 hours.
After completion of the reaction, purification was performed by Florisil column chromatography, and 4-t-butyldioxy-4-methyl-2,5
1.01 g of cyclohexadien-1-one was obtained. Example 2 0.272 g of p-isopropylphenol, RuCl
_To a mixture of 0.058 g of ₂ (PPh ₃ ) ₃ and 2 ml of anhydrous benzene was added a solution of 3.59 molar t-butyl hydroperoxide in benzene at room temperature under an argon atmosphere.
ml was added dropwise over 2 hours, and the mixture was further stirred at the same temperature for 3 hours. After completion of the reaction, purification was carried out by florisil column chromatography to obtain 0.381 g of 4-t-butyldioxy-4-isopropyl-2,5-cyclohexadien-1-one. Yield: 86% Example 3 The same operation as in Example 2 was carried out except that 0.335 g of p-phenylphenol was used instead of p-isopropylphenol, and 4-t-butyldioxy-4-phenyl-2,5 was used. -0.386 g of cyclohexadiene-1-one
Got. Example 4 5,6,7,8-tetrahydro-2-naphthol
To a mixture of 889 g, 0.17 g of RuCl ₂ (PPh ₃ ) ₃ and 6 ml of anhydrous benzene, 6.7 ml of a benzene solution of 3.6 molar t-butyl hydroperoxide in benzene was added dropwise over 2 hours at room temperature under an argon atmosphere. Then, the mixture was further stirred at the same temperature for 3 hours. After completion of the reaction, purification was carried out by florisil column chromatography to obtain 1.217 g of 1-tert-butyldioxybicyclo [4.4.0] decal 2,5-dien-4-one. Yield 85% Example 5 0.267 g of 5-indanol, RuCl ₂ (PPh ₃ ) ₃
To a mixture of 0.058 g and 2 ml of anhydrous benzene, 2.4 ml of a 3.3 molar tert-butyl hydroperoxide benzene solution was added dropwise over 2 hours at room temperature under an argon atmosphere, and then stirred at the same temperature for another 3 hours. did. After completion of the reaction, the reaction mixture was purified by florisil column chromatography, and 1-t-butyldioxybicyclo [4.3.0] was used.
0.32 g of noner 2,5-dien-4-one was obtained.
68% yield

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-263687 (JP, A) JP-A-6-263673 (JP, A) JP-A-51-105038 (JP, A) JP-A-48-48 97848 (JP, A) JP-A-46-4620 (JP, A) JP-T-Hei 8-5044437 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 409/18 C07C 407 / 00

Claims (1)

(57) [Claims] [Claim 1] General formula 2 (Wherein, R represents an alkyl group or a phenyl group which may be substituted, R ¹ , R ² , R ³ and R ⁴ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) R and R ¹ may be bonded to each other to form a ring.) A phenol represented by the general formula characterized by reacting with t-butyl hydroperoxide in the presence of a ruthenium catalyst. Chemical 1 (Wherein R and R ^{1 to} R ⁴ have the same meanings as described above), and a process for producing 4-t-butyldioxy-2,5-cyclohexadien-1-ones represented by the formula: