JPH11209314A - Production of cyclooctadienes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To industrially and advantageously produce the subject compound useful as a synthetic intermediate for medicines, perfumes, etc., in an inexpensive and readily handleable solvent in high regioselectivity by reacting conjugated dienes in the presence of a specific catalyst in a hydrophilic solvent. SOLUTION: (A) A compound of formula I (R<1> is H, a 1-3C alkyl or a 2-3C alkenyl) is reacted in the presence of (C) a divalent ruthenium compound e.g. a compound obtained by reacting a compound of the formula, [Ru(L<6> )(L<1> )]X2 [L<6> is a ligand comprising a (substituted)six-membered aromatic ring; L<1> is a (substituted)pyri(mi)dine derivative; X is a halogenl with a compound of the formula, MX'm [M is an alklali (earth)metal, a transition metal or lanthanoid; X' is a nonassociating anion; (m) is 1-4 valence of M]} in (B) a hydrophilic solvent (e.g. water, a lower alcohol or mixed solvent thereof) to provide the objective compound of formula II. The reaction is preferably carried out at 70-120 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing cyclooctadienes starting from butadiene or 2-substituted-1,3-butadienes. More specifically, the present invention relates to a method for producing cyclooctadienes by dimerizing or co-dimerizing and cyclizing the above-mentioned starting material.

[0002]

2. Description of the Related Art There have been reported many methods for producing a low polymer such as a dimer by forming a carbon-carbon bond by low polymerization of butadiene or isoprene. For example, low polymerization of isoprene has been reviewed since 154 pages of the Society of Organic Synthesis 1983. When this isoprene is polymerized, two types of bonding modes can occur: the so-called head-to-head and head-to-tail bonding. Then, when dimerizing isoprene and cyclizing to obtain cyclooctadiene, whether to obtain cyclooctadiene having a main head-head bond or to obtain cyclooctadiene having a main head-tail bond Control, that is, the isoprene 2 in cyclooctadiene
The polymerization technique for controlling the position of the methyl group at the position (hereinafter referred to as substituent regioselectivity) has not yet been completed. Further, a polymerization technique for producing cyclooctadiene in which the position of a double bond is specified (hereinafter referred to as double bond position selectivity) has not yet been completed. (Hereinafter, the regioselectivity of the substituent and the regioselectivity of the double bond are collectively referred to as regioselectivity). Recently, a dimerization reaction of isoprene with enhanced regioselectivity using divalent ruthenium as a catalyst has been reported (Organometallics 1994, 13, 1).
020). Although this method has significantly improved position selectivity as compared with the prior art, it is not sufficiently satisfactory, and a higher position selectivity is desired.

On the other hand, it is also known that a divalent ruthenium compound containing cyclooctadiene is a compound that catalyzes a co-dimerization reaction between a compound having a terminal triple bond and a compound having a terminal double bond. Yes (Angew. Ch
em. Int. Ed. Engl. 1995, 34, 25
9). In this case, it is essential to use a compound having a triple bond having a relatively high reaction activity, and there is no disclosure of polymerizing only a compound having a relatively low reaction activity such as isoprene or preparing a cyclic compound. Further, in this technique, a compound having a triple bond at a terminal is relatively expensive and difficult to obtain, and furthermore, there is a problem that detailed attention is required in operation and industrially disadvantageous.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems which have been conventionally known, that is, without using a solvent which is expensive and industrially difficult to handle industrially, a conjugate of isoprene or butadiene can be used. An object is to produce cyclooctadienes from dienes. Another object of the present invention is to provide a method for producing cyclooctadienes having high regioselectivity. Another object of the present invention is to provide a method for producing cyclooctadienes which is inexpensive and industrially advantageous.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, when a hydrophilic solvent is particularly selected as a solvent used in the reaction, the low polymerization reaction of the conjugated diene monomer is reduced. It has been found that cyclooctadienes can be obtained with high regioselectivity. That is, in a hydrophilic solvent, when a conjugated diene monomer is reacted in the presence of a divalent ruthenium compound, it is found that cyclooctadienes can be obtained with high regioselectivity. The present invention has been completed. That is, the present invention provides the following general formula (1)

Embedded image (1) wherein R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 to 3 carbon atoms, in a hydrophilic solvent. Reacting in the presence of a divalent ruthenium compound;

Embedded image (2) A method for producing a cyclooctadiene represented by the following formula:

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The conjugated dienes referred to in the present invention include butadiene or 2
Lower alkyl having 1 to 3 carbon atoms or 2 to 3 carbon atoms
Is a butadiene derivative having an alkenyl substituent.
Examples of the lower alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group and the like.
Examples of the alkenyl groups 3 to 3 include a propenyl group. Preferred alkyl groups are a methyl group and an ethyl group, and a more preferred alkyl group is a methyl group. One or more of these conjugated dienes are used as starting materials. Among R ¹ of cyclooctadienes represented by the formula (1), which is a reaction product of the present invention, a hydrogen atom,
A methyl group and an ethyl group are preferred.

The divalent ruthenium compound used in this reaction includes the following general formula (3) [Ru (L ⁶ ) (L ¹ )] X ₂ (3) (where L ⁶ has a substituent And X represents a halogen atom, and L ¹ is a pyridine derivative optionally having a substituent or a pyrimidine derivative optionally having a substituent. And a compound represented by the following general formula (4) MX′m (4) (wherein M is an alkali metal, alkaline earth metal, transition metal, or lanthanoid, and X ′ represents a non-associative anion; m is 1 to 4 and is the same as the valence of M.)
And the compounds obtained by reacting Also,

(A) A ruthenium compound represented by the following general formula (5): Ru (L ⁶ ) X ₂ (5) (wherein L ⁶ and X are the same as described above), and (b) (i) ) A pyridine derivative optionally having a substituent or a pyrimidine derivative optionally having a substituent, (ii), R ¹⁴ -A-NH- (C (R ¹⁵ )
(R ¹⁶ )) _q -C (R ¹⁷ ) (R ¹⁸ ) -C
(R ¹⁹ ) (R ²⁰ ) —NH ₂ or (iii) R ^{31
-N = C (R 32) -} (C (R 33) (R 34)) r -
(C ( ^R35 ) ( ^R36 )) _s- (C ( ^R37 ) (R
_{^{38)) t, - (C}} (R 39) (R 40)) u -C (R
⁴¹ ) = NR ⁴² (wherein R ^{14 to} R ²⁰ may be the same or different and represent a hydrogen atom, an aryl group or a lower alkyl group having 1 to 4 carbon atoms, and A represents —S—, -S
O ₂ —, —P (R ²¹ ) — and —P (O) (R ²² ) —, wherein R ²¹ and R ²² may be the same or different;
A hydrogen atom, an aryl group or a lower alkyl group having 1 to 2 carbon atoms, q is 0 or 1, and R ³¹ , R ⁴²
May be the same or different and are an aryl group which may have a lower alkyl having 1 to 4 carbon atoms, a lower alkyl group having 1 to 4 carbon atoms, an aralkyl group or a lower alkenyl group having 2 to 4 carbon atoms. , R ³² and R ⁴¹ may be the same or different, and may have a lower alkyl having 1 to 4 carbon atoms, an lower alkyloxy having 1 to 4 carbon atoms which may have a substituent or A hydrogen atom, R ³¹ and R
³² or R ⁴¹ and R ⁴² may form a ring that may contain oxygen, r, s, t, and u are 0 or 1, and R ^{33 to} R ⁴⁰ are the same or different. It may be different and is hydrogen or a lower alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms. In addition, R ³³ ~
Any two of R ⁴⁰ may be mutually bonded to form a 5- or 6-membered ring which may have a substituent. And (c) in the presence of a compound represented by the following general formula (4) MX′m (4) (wherein M and m are the same as described above). be able to.

Among these compounds, a compound represented by the general formula (7) [Ru (L ⁶ ) (L ³ )] X ′ (7) or a compound represented by the general formula (8) [Ru (L ⁶ ) (L ⁴ )] A compound represented by X ′ ₂ (8) (wherein L ³ is —N (A ′)-(C
_{^{(R 15) (R 16)}} ) q -C (R 17) (R 18) -
Consisting of C (R ¹⁹ ) (R ²⁰ ) —NH ₂ , wherein A ′ is —A
A -R ^{14, L 4} is ^{R 31 -N = C (R 32} ) -
(C (R ³³ ) (R ³⁴ )) _r- (C (R ³⁵ ) (R
³⁶ )) _s- (C ( ^R37 ) ( ^R38 )) _t- (C (R
^{39) (R} ₄₀₎₎ consists ^{u -C (R 41) = N} -R 42, R 14 ~R 22, R 31 ~R 42, A, q, r,
s, t, u, L ⁶ and X ′ are the same as above. ) Is preferred.

The starting materials for preparing the divalent ruthenium compound will be described. First, a compound represented by the general formula (3) is a pyridine derivative optionally having a substituent or a pyrimidine derivative optionally having a substituent,
A ruthenium compound in which a six-membered aromatic ring which may have a substituent and a halogen atom are coordinated is preferable. Specific examples of the 6-membered aromatic ring which may have a substituent include benzene, p-cymene, mesitylene and the like. As the substituent in the pyridine derivative which may have a substituent or the pyrimidine derivative which may have a substituent,
An alkyl group having 1 to 3 carbon atoms, an alkylamino group and the like are preferable. Examples of the pyridine derivative or the pyrimidine derivative which may have a substituent include pyridine, lutidine, pyrazine, N, N-dimethylaminopyridine, pyrimidine and the like. These compounds are suitable because commercially available products can be used.

The compound represented by the general formula (3) can be prepared by a known method. Specifically, for example, ruthenium benzene dichloride is stirred at room temperature for 90 hours in 30 volumes of pyridine. The resulting precipitate is washed and dried to obtain (pyridine) (benzene) ruthenium dichloride.

Next, the compound represented by formula (5) will be described. In the compound represented by the general formula (5), a ligand comprising a 6-membered aromatic ring which may have a substituent or a cyclooctadiene which may have a substituent in a ruthenium compound. The position state is as widely known in the field of ruthenium compound chemistry, wherein the ligand is coordinated to a ruthenium atom. Benzene is particularly preferred as the ligand composed of the six-membered aromatic ring, and as the substituent, an alkyl group having 1 to 3 carbon atoms is preferred. Specific examples of the ligand comprising a six-membered aromatic ring which may have a substituent include benzene, p-cymene, mesitylene and the like. As the halogen atom of the compound represented by the general formula (5), a chlorine atom, a bromine atom, an iodine atom and the like are preferable.

Examples of preferred compounds represented by the above general formula (5) include ruthenium benzene dichloride, ruthenium p-cymene dichloride, ruthenium mesitylene dichloride, ruthenium benzene dibromide, and ruthenium p-cymene dibromide , Ruthenium mesitylene dibromide, ruthenium benzene diiodide, ruthenium p-cymene diiodide ruthenium mesitylene diiodide, ruthenium cyclooctadiene dichloride, ruthenium cyclooctadiene dibromide, ruthenium cyclooctadiene diiodide, etc. Can be mentioned.

The compound represented by the above general formula (5) is prepared by a known method. For example, it can be prepared by heating and stirring cyclohexadiene in ethanol for 3 hours (Journal of Chemical Society Dalton 1974, p. 233).

The component (b) to be reacted with the general formula (5) will be described. First, the component (b) (i) is a pyridine derivative which may have a substituent or a pyrimidine derivative which may have a substituent. The above compounds may be used as these derivatives.

(B) In the component (ii), R ^{14 to} R
²⁰ is a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group or a propyl group or an aryl group such as a phenyl group; R ²¹ and R ²² are a hydrogen atom;
Examples thereof include an aryl group such as a phenyl group and a tolyl group, and a lower alkyl group having 1 to 2 carbon atoms. As the ligand comprising a 6-membered aromatic ring which may have a substituent, those already described can be used. As the non-associative anion, any anion may be used as long as it has poor covalent bonding with the central metal of the metal complex and easily dissociates from the central metal and has a property of giving the complex a cationic property. Specific examples include trifluoromethanesulfonic acid, tetrafluoroboric acid, and hexafluorophosphoric acid.

(B) R ³¹ to (iii) in the component
Specific examples of R ⁴² is a lower alkyl group having a carbon number of 1-4 such as methyl group, ethyl group, phenyl group, an aryl group such as a tolyl group, a methoxy group, an alkoxy group such as ethoxy group. R ³¹ and R ³² , and R ⁴¹ and R ⁴² may be mutually bonded to form a pyridine ring or an oxazoline ring. Further, any two of R ^{33 to} R ⁴⁰ may be bonded to each other, and the portion connecting the imine sites may form a ring such as a phenyl group or a naphthyl group.
(B) Specific examples of the bidentate ligand of the component (iii) include 2,2'-bipyridine, 2,2'-bis (4-benzyl-2-oxazoline), and 2,2'-methylenebis (4-
Phenyl-2-oxazoline), 2,2′-bis [(2
-Oxazolinyl) naphthyl] and the like.

M in MX'm is preferably silver, lanthanum, samarium, cerium, etc., and X 'is trifluoromethanesulfonic acid, tetrafluoroboric acid, perchloric acid, pentafluorophosphoric acid, nonafluorobutane. Sulfonic acid and the like are preferred. Specific examples of MX'm include silver triflate, lanthanum (III) triflate, potassium nonafluorobutanesulfonate, and the like.

The above components (a) and (b) are represented by the formula (4)
By reacting in the presence of the compound represented by the formula, the divalent ruthenium compound of the present invention can be obtained, and the reaction conditions at 0 ° C. to 200 ° C. for about 1 hour to 72 hours are sufficient.

The preferred divalent ruthenium compound of the present invention has the general formula (9)

Embedded image (9) (wherein, R ^{8 to} R ^{20 each} represent hydrogen, an aryl group or a lower alkyl group having 1 to 4 carbon atoms, and any two of R ^{8 to} R ¹³ may be substituted with 5 to 5 carbon atoms together with Or a 6-membered ring, and X ′ is the same as described above), or a compound represented by the general formula (10):

Embedded image (10) (wherein, R ^{8 to} R ¹³ R, R ^{31 to} R ⁴² , r, s,
t, u and X 'are the same as above. ). Preferred R ^{8 to} R ²⁰ are a hydrogen atom,
Examples include a methyl group, an ethyl group, a propyl group, a phenyl group, and a tolyl group. In addition, any two of R ^{8 to} R ¹³ are formed together with the carbon atom to which they are bonded.
Examples of the six-membered ring or the six-membered ring include an indenyl ring and a fleonyl ring which may have a substituent, and examples of the substituent include a hydroxy group, a carboxyl group, a nitro group, and a fluorine atom. In addition, two or more substituents may be used.

Specific preferred examples of the divalent ruthenium compound corresponding to the general formula (9) include (N-2-aminoethyl-p-toluenesulfonamide) (η ⁶ -benzene) ruthenium trifluoromethanesulfonate , (N
-2-aminoethyl-p-toluenesulfonamide)
(Η ⁶ -p-cymene) ruthenium trifluoromethanesulfonate, (N-2-aminoethyl-p-toluenesulfonamide) (η ⁶ -mesitylene) ruthenium trifluoromethanesulfonate, (N-2-aminoethyl-p-
Toluenesulfonamide) (η ⁶ -benzene) ruthenium tetrafluoroborate, (N-2-aminoethyl-p
-Toluenesulfonamide) (η ⁶ -p-cymene) ruthenium tetrafluoroborate, (N-2-aminoethyl-p-toluenesulfonamide) (η ⁶ -mesitylene)
Ruthenium tetrafluoroborate, (N-2-aminoethyl-p-toluenesulfonamide) (η ⁶ -benzene) ruthenium hexafluorophosphate, (N-2-aminoethyl-p-toluenesulfonamide) (η ^6- p-
(Cymene) ruthenium hexafluorophosphate, (N-2-
Aminoethyl-p-toluenesulfonamide) (η ⁶ −
(Mesitylene) ruthenium hexafluorophosphate and the like. Here, η ^m means that the number of coordinating electrons is m. Specifically, η ⁶ means that the number of coordinated electrons is 6. As a specific preferred example of the divalent ruthenium compound corresponding to the general formula (10), a divalent ruthenium compound prepared from a preferred compound in the starting materials will be described in order to avoid complexity.

The divalent ruthenium compound can be prepared by a known method. For example, (N-2-aminoethyl-P-toluenesulfonamide) (aryl)
Using ruthenium (II) chloride as a precursor, 1
It is obtained by adding an equivalent amount of silver triflate at room temperature and stirring. Alternatively, (N-2-aminoethyl-P-
Toluenesulfonamide) (aryl) Two-phase system of water (100 times the volume of the ruthenium complex) and methylene chloride (100 times the volume of the ruthenium complex) in the presence of one equivalent of sodium triflate phase transfer catalyst At room temperature for 7 hours, and the organic layer is separated and concentrated.

As a divalent ruthenium compound different from the above-mentioned divalent ruthenium compound, a compound represented by the following general formula (6): Ru (L ⁵ ) (L ² ) X (6) (where L ⁵ may have a substituent. 5- shows a ligand consisting of an aromatic ring of ring, L ² is double with 5-11 straight chain unsaturated hydrocarbon or carbon atoms having two or more double bonds at 4-6 carbon atoms A ligand composed of a cyclic unsaturated hydrocarbon having two or more bonds, wherein X is the same as defined above).

The coordination state in the ruthenium compound of the ligand consisting of a 5-membered aromatic ring which may have a substituent and is L ⁵ in the compound represented by the general formula (6) is a ruthenium compound As is widely known in the field of chemistry, for example, a ligand composed of a five-membered aromatic ring is attached to a ruthenium atom in a state where one hydrogen atom of the aromatic ring is removed and an anion-like state is present. Rank.

As the linear unsaturated hydrocarbon having 4 to 6 carbon atoms and having two or more double bonds, butadiene, dimethylbutadiene, isoprene, pentadiene, hexadiene and the like are preferable. Examples of the cyclic unsaturated hydrocarbon having two or more double bonds in 11 include cyclopentadiene, cyclohexadiene, cyclooctadiene, benzene, p-cymene, mesitylene and the like. Examples of the 5-membered aromatic ring which may have a substituent include cyclopentadienyl, tetramethylcyclopentadienyl, pentamethylcyclopentadienyl, indenyl and the like. The halogen atom is preferably a chlorine atom, a bromine atom, an iodine atom or the like.

A preferred ruthenium compound is represented by the general formula (1)
1)

Embedded image (11) (wherein, R ³ to R ^{7 each} represent a hydrogen atom or a carbon number of 1 to
4 represents a lower alkyl group, and any two of R ³ to R ⁷ may form a 5- or 6-membered ring with the carbon atom to which they are bonded, and L ² and X are the same as defined above. ).

Preferred examples of R ^{3 to} R ⁷ include a hydrogen atom, a methyl group, an ethyl group, a propyl group and a phenyl group. Examples of the 5- or 6-membered ring formed by bonding any two of the above R ^{4 to} R ⁷ together with the carbon atom to which they are attached include an indenyl ring and a fleonyl ring which may have a substituent. Examples of the substituent include a hydroxy group, a carboxyl group, a nitro group, and a fluorine atom. In addition, two or more substituents may be used.

[0028] Specific preferred examples of the general formula (11) corresponding to the divalent ruthenium compound, (eta ⁵ - pentamethylcyclopentadienyl) (eta ⁴ - isoprene)
Ruthenium (II), (η ⁵ - pentamethylcyclopentadienyl) (eta ^{4-1,5-cyclooctadiene)} ruthenium chloride (II), (η ⁵ - pentamethylcyclopentadienyl) (eta ⁴ - 1,3-butadiene) ruthenium chloride (II), (η ⁵ - pentamethylcyclopentadienyl) (eta ^{4-2,3-dimethyl} 1,3-butadiene) ruthenium chloride (II), (η ⁵ - cyclopenta Dienyl) (η ⁴ -isoprene) ruthenium chloride (I
I), (η ⁵ - cyclopentadienyl) (η ⁴ -1,5
-Cyclooctadiene) ruthenium (II) chloride, (η
⁵ -cyclopentadienyl) (η ⁴ -1,3-butadiene) ruthenium (II) chloride, (η ⁵ -cyclopentadienyl) (η ⁴ -2,3-dimethyl1,3-butadiene) ruthenium chloride ( II) and the like.

The divalent ruthenium compound corresponding to the general formula (11) is produced by a known method. For example,
Organometallics, 1993 (12),
2221 and Experimental Chemistry 18 can be prepared according to the organometallic complex. Specifically, for example, pentamethylcyclopentadienyl ruthenium (III) chloride and 1 equivalent of zinc powder are suspended at 0 ° C. in methanol (100 times the volume of the ruthenium complex), and 30 equivalents of isoprene are added. Was. After the reaction for 15 minutes, the solid was filtered off, and the obtained solution was concentrated to obtain a crude product, which was recrystallized from ethanol to obtain a divalent ruthenium compound corresponding to the general formula (11).

As the hydrophilic solvent which is one of the features of the present invention, water, lower alcohol or a mixed solvent thereof can be used. For example, methanol, ethanol, hydrous ethanol and the like can be mentioned. Further, other solvents may be used in an amount not to impair the effects of the present invention. Other solvents include dimethylformamide, dimethylimidazolidinone, N-methylpyrrolidone, and the like. For example, a preferable result was obtained even when a mixed solvent in which dimethylformamide was mixed with water in an equivalent amount was used.

More specifically, the method for producing the cyclooctadiene of the present invention will be described. The parent solvent is 0.1 to 25 times, preferably 0.8 to 3 times, the volume of the starting material.
The divalent ruthenium compound was added in an amount of 0.00
1 to 50 mol%, preferably 0.08 to 10 mol%
So that The reaction temperature is 0 ° C to 200 ° C, preferably 70 ° C to 120 ° C, and the reaction time is 1 hour to 72 hours, preferably 7 hours to 24 hours. The above reaction usually proceeds in an atmosphere of an inert gas such as nitrogen gas or argon gas, but may be carried out in a gas atmosphere of a starting material. In the present invention, a compounding agent can be added to the reaction solution as needed. Examples of the compounding agent include lithium chloride, silver triflate, lanthanum triflate, and samarium triflate.

[0032]

EXAMPLES The present invention will be described below in more detail with reference to Comparative Examples and Examples, but the present invention is not limited thereto. 1. The chemical purity of the product was measured by gas chromatography (GLC). The conditions are as described below. Analyzer used: Pured Packard HP589
0 Series II Gas Chromatograph Column: Neutrabond-10.25mm x
1. 30m detector: FID The product was identified by NMR spectrum and comparison with known literature. NMR: GE manufactured by Varian
MINI2000 ⁽¹ H, 200MHz)

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

EXAMPLE 1 (eta ⁵ - pentamethylcyclopentadienyl) (eta ⁴ - isoprene) ruthenium chloride (II) (5
1 mg, 0.15 mmol) in ethanol (10 m
l), water (5 ml), isoprene (15 ml, 0.15
mol), and heated and stirred at 100 ° C. for 20 hours in a sealed tube. The reaction solution was separated, and the organic layer was dried and distilled to obtain 4.1 g (41%) of 3,7-dimethyl-1,1.
5-cyclooctadiene was obtained. Regioselectivity was 92%. NMR (CDCl ₃ , δ): 1.01 (6H, d),
2.00-2.20 (2H, m), 2.22-2.40
(2H, m), 2.83-3.05 (2H, m), 5.
20-5.35 (2H, m), 5.40-5.55 (2
H, m)

[0035]

EXAMPLES (N-2-aminoethyl-p-toluenesulfonamide) (η ⁶ -benzene) ruthenium chloride (I
I) (83 mg) was dissolved in methanol (10 ml),
75 mg of silver triflate and isoprene (10 ml) were added, and the mixture was heated and stirred at 100 ° C. for 24 hours in a sealed tube. The reaction solution was poured into water, and the organic layer was separated. By distillation,
3,7-Dimethyl-1,5-cyclooctadiene was obtained. The selectivity was 78% and the NMR was consistent with that shown in Example 1.

EXAMPLE 3 (eta ⁵ - pentamethylcyclopentadienyl) (eta ⁴ - isoprene) ruthenium (II) chloride
(3.0 mg) in methanol (1.5 ml),
It was placed in a sealed tube, the inside of the system was replaced with butadiene, and heated and stirred at 100 ° C. for 8 hours to obtain 1,5-cyclooctadiene.

[0036]

[Comparative Example 1] (eta ⁵ - pentamethylcyclopentadienyl) (eta ⁴ - isoprene) ruthenium (II) chloride
(7.5 mg, 22 mmol), silver triflate (8 m
g, 31 mmol) in tetrahydrofuran (2.5 m
l) and diethyl ether (1 ml) were suspended in a mixed solvent. Isoprene (2.4 ml) was added thereto, and the mixture was heated and stirred at 90 ° C. for 13 hours in a sealed tube. The reaction solution was quenched with water, and the organic layer was analyzed by GLC.
A measurement was made. GLC analysis revealed that the 3,3 in the dimer region
Regioselectivity as 7-dimethyl-1,5-cyclooctadiene was about 75%.

[0037]

Example 4 Ruthenium benzene dichloride (200 mg,
0.8 mmol), 2,2'-methylenebis (4-phenyl-2-oxazoline) (250 mg, 0.82 mm
ol), silver triflate (380 mg, 1.48 mmol)
l) was dissolved in 10 mL of methanol, and 10 m of isoprene was dissolved.
L (6.8 g, 100 mmol) was added, and the mixture was heated and stirred for 7 hours under an argon atmosphere in a sealed tube. The reaction mixture is filtered,
By distilling, a cyclized dimer was obtained. (Dimer / selectivity 80% Isomer 12% Dipentene 8%)

[0038]

Example 5 Ruthenium pyridine dipyridine pyridine (6.
6 mg, 0.02 mmol), silver triflate (5.2
(0.02 mmol) was dissolved in 2 mL of methanol, 2 mL (1.4 g, 20 mmol) of isoprene was added, and the mixture was heated and stirred for 16 hours in a sealed tube under an argon atmosphere.
The reaction mixture was diluted with water, and the organic layer was analyzed by GC. As a result, the product was found to have a dimer / selectivity of 79%, an isomer of 16%, and dipentene of 5%.

[0039]

According to the present invention, high-purity cyclooctadene can be produced at a low cost by a simple method. That is, by using a hydrophilic solvent which is inexpensive and has excellent handling properties, cyclooctadenes having regioselectivity equal to or higher than that of the conventional production method could be produced by a simple method. Moreover, it has become possible to obtain cyclooctadienes without using a rather expensive compound such as silver triflate. These cyclooctadienes are extremely important compounds as intermediates for synthesizing pharmaceuticals or synthetic intermediates of flavors and other various useful compounds.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Takenobu Nishikawa 1-4-11, Nishi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Takasago International Corporation

Claims (7)

[Claims] (1) The following general formula (1): (1) wherein R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 to 3 carbon atoms, in a hydrophilic solvent. The reaction is carried out in the presence of a divalent ruthenium compound, characterized by the following general formula (2): (2) A method for producing a cyclooctadiene represented by the following formula: 2. A divalent ruthenium compound represented by the following general formula (3): [Ru (L ⁶ ) (L ¹ )] X ₂ (3) (where L ⁶ is a 6-membered group which may have a substituent) X represents a halogen atom, and L ¹ represents a pyridine derivative which may have a substituent or a pyrimidine derivative which may have a substituent. .)
And the following general formula (4) MX′m (4) (wherein M is an alkali metal, alkaline earth metal, transition metal, or lanthanoid, X ′ represents a non-associative anion, and m represents 1 to 4) And the same as the valence of M).). The process for producing cyclooctadienes according to claim 1, wherein 3. A divalent ruthenium compound comprising: (a) a compound represented by the following general formula (5): Ru (L ⁶ ) X ₂ (5) wherein L ⁶ is a six-membered aromatic ring which may have a substituent; A ligand composed of a ring or a cyclooctadiene which may have a substituent, and X represents a halogen atom); and (b) (i) a ruthenium compound having a substituent A good pyridine derivative or a pyrimidine derivative optionally having a substituent (ii), R ¹⁴ -A-NH- (C (R ¹⁵ )
(R ¹⁶ )) _q -C (R ¹⁷ ) (R ¹⁸ ) -C
(R ¹⁹ ) (R ²⁰ ) —NH ₂ or (iii) R ^{31
-N = C (R 32) -} (C (R 33) (R 34)) r -
(C ( ^R35 ) ( ^R36 )) _s- (C ( ^R37 )) (R
_{^{38)) t - (C (}} R 39) (R 40)) u -C (R
⁴¹ ) = NR ⁴² (wherein R ^{14 to} R ²⁰ may be the same or different and represent a hydrogen atom, an aryl group or a lower alkyl group having 1 to 4 carbon atoms, and A represents —S—, -S
O ₂ —, —P (R ²¹ ) — and —P (O) (R ²² ) —, wherein R ²¹ and R ²² may be the same or different;
A hydrogen atom, an aryl group or a lower alkyl group having 1 to 2 carbon atoms, q is 0 or 1, and R ³¹ , R ⁴²
May be the same or different and are an aryl group which may have a lower alkyl having 1 to 4 carbon atoms, a lower alkyl group having 1 to 4 carbon atoms, an aralkyl group or a lower alkenyl group having 2 to 4 carbon atoms. , R ³² and R ⁴¹ may be the same or different, and may have a lower alkyl having 1 to 4 carbon atoms, an lower alkyloxy having 1 to 4 carbon atoms which may have a substituent or A hydrogen atom, R ^{31 and R
32} or R ⁴¹ R ⁴² may form a ring that may contain oxygen, r, s, t, and u are 0 or 1, and R ^{33 to} R ⁴⁰ are the same or different. And may be hydrogen or a lower alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms. Also, R ^{33 to} R
Any two groups of the groups ⁴⁰ may be mutually bonded to form a 5- or 6-membered ring which may have a substituent. And (c) the following general formula (4) MX′m (4) (wherein M is an alkali metal, alkaline earth metal, transition metal, or lanthanoid, and X ′ represents a non-associative anion; m is 1 to 4 and is the same as the valence of M.) The process for producing cyclooctadienes according to claim 1, which is a compound obtained by reacting in the presence of a compound represented by the formula: 4. A divalent ruthenium compound represented by the following general formula (6): Ru (L ⁵ ) (L ² ) X (6) wherein L ⁵ is a 5-membered aromatic ring which may have a substituent. It indicates ligand consisting of ring, L ² is 4-6 double bonds straight-chain unsaturated hydrocarbon or carbon atoms having two or more of 5-11 double bond two or more carbon atoms Wherein X represents a ligand comprising a cyclic unsaturated hydrocarbon and X represents a halogen atom.) The method for producing cyclooctadienes according to claim 1, wherein 5. A compound represented by the following general formula (7) [Ru (L ⁶ ) (L ³ )] X ′ (7) or a divalent ruthenium compound represented by the following general formula (8): [Ru (L ⁶ ) (L ⁴ )] X ′ ₂ (8) (wherein L ⁶ is a 6-membered aromatic ring which may have a substituent or a cyclooctadiene which may have a substituent indicates ligand consisting of, ^{L 3} is -N (a ')
-(C (R ¹⁵ ) (R ¹⁶ )) _q -C (R ¹⁷ ) (R
¹⁸ ) represents a ligand consisting of —C (R ¹⁹ ) (R ²⁰ ) —NH ₂ , wherein A ′ is —A—R ¹⁴ and R ^{14 to} R ²⁰
May be the same or different and represent a hydrogen atom, an aryl group or a lower alkyl group having 1 to 4 carbon atoms, and A is-
^{_{S -, - SO 2 -,}} - P (R 21) -, - P (O) (R
²² )-, wherein R ²¹ and R ²² may be the same or different and each have a hydrogen atom, an aryl group or a carbon number of 1 to 2;
L ⁴ represents R ³¹ —N ＝ C (R
³² )-(C ( ^R33 ) ( ^R34 )) _r- (C
( ^R35 ) ( ^R36 )) _s- (C ( ^R37 )
_{^{(R 38)) t - (}} C (R 39) (R 40)) u -C
A ligand consisting of (R ⁴¹ ) = NR ⁴² ,
R ³¹ and R ⁴² may be the same or different, and may be an aryl group which may have a lower alkyl having 1 to 4 carbon atoms, a lower alkyl group having 1 to 4 carbon atoms, an aralkyl group or a lower alkyl having 2 to 4 carbon atoms. A lower alkenyl group, R ³² and R ⁴¹ may be the same or different, and may have a lower alkyl group having 1 to 4 carbon atoms, an aryl group having 1 to 4 carbon atoms and 1 to 4 carbon atoms which may have a substituent. R ³¹ and R ³² or R ⁴¹ and R ⁴² may form a ring which may contain oxygen, and r, s,
t and u are 0 or 1, and R ^{33 to} R ⁴⁰ may be the same or different and are hydrogen, a lower alkyl group having 1 to 4 carbon atoms, or an alkenyl group having 2 to 4 carbon atoms.
In addition, any two groups of R ^{33 to} R ⁴⁰ may be mutually bonded to form a 5- or 6-membered ring which may have a substituent, and q is 0 or 1. Wherein X ′ is a non-associative anion). 6. The process according to claim 1, wherein the hydrophilic solvent is methanol or hydrous ethanol. 7. The process according to claim 1, wherein the conjugated diene is isoprene or butadiene.