IMPROVED PROCESS TO PRODUCE SPECIFIC ALPHA,BETA-UNSATURATED CARBOXYLATES

Abstract

The present invention relates to a process for producing specific α,β-unsaturated carboxylates.

Claims

1. Process for the production of a compound of formula (I) ##STR00026## wherein R.sub.1 is a C.sub.1-C.sub.4-alkyl moiety, preferably —CH.sub.3 or —CH.sub.2CH.sub.3, and R.sub.2 is ##STR00027## (the * is showing where the bond is localized), and wherein a compound of formula (II) ##STR00028## is reacted with a compound of formula (III) ##STR00029## wherein the R.sub.1 and R.sub.2 have the same meanings as defined above for the compound of formula (I) in the presence of at least one catalyst of formula (IV) ##STR00030## wherein R.sub.3, R.sub.4, R.sub.5 and R.sub.6 signify independently from each other —CH.sub.3, —OCH.sub.3, —NO.sub.2 or halogen, and W, X, Y and Z signify independently from each other a neutral or ionic ligand, wherein W, X, Y and Z can be monodentate or bidentate with the proviso that the Ru is always six times coordinated, and m, n, o and p signify an integer 0, 1, 2 or 3 q signifies an integer 1, 2, 3 or 4.

2. Process according to claim 1, wherein R.sub.1 is —CH.sub.3 or —CH.sub.2CH.sub.3.

3. Process according to claim 1, wherein R.sub.2 is ##STR00031##

4. Process according to claim 1, wherein the compounds of formula (Ia) and (Ib) ##STR00032## are produced.

5. Process according to claim 1, wherein the catalyst of formula (IVa) ##STR00033## is used.

6. Process according to claim 1, wherein the catalyst of formula (IVb) ##STR00034## is used.

7. Process according to claim 1, wherein the catalyst of formula (IVc) ##STR00035## wherein R.sub.7 is H or CH.sub.3 is used.

8. Process according to claim 1, wherein the substrate (starting material) to catalyst ratio (mol-based) is 5000:1 to 10:1.

9. Process according to claim 1, wherein the process is carried out without any solvent.

10. Process according to claim 1, wherein the process is carried out in at least one apolar aprotic organic solvent.

11. Process according to claim 10, wherein the apolar aprotic organic solvent is chosen from the group consisting of aliphatic hydrocarbons, cyclic hydrocarbons aromatic hydrocarbons and carboxylate esters.

12. Process according to claim 1, wherein the process is carried out at a temperature of between −5° C. and 60° C.

13. Process according to claim 1, wherein the compound of formula (V) ##STR00036## is added to the reaction mixture.

14. Process according to claim 13, wherein the compound of formula (V) is added in amount of 0.01-0.75 mol equivalent (in regard of compound of formula (II)).

15. Compounds of formulae (IV′), (IV″) and (IV′″) ##STR00037## wherein R.sub.3, R.sub.4, R.sub.5 and R.sub.6 signify independently from each other —CH.sub.3, —OCH.sub.3, —NO.sub.2 or halogen, and W, X, Y and Z signify independently from each other a neutral or ionic ligand, wherein W, X, Y and Z can be monodentate or bidentate with the proviso that the Ru is always six times coordinated, and m, n, o and p signify an integer 0, 1, 2 or 3 q signifies an integer 1, 2, 3 or 4.

16. Compounds of formulae (IVa), (IVb), (IVc′) and (IVc″) ##STR00038##

Description

EXAMPLES

Example 1

[0086] 3-Methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)pent-1-en-4-yn-3-ol (2.33 g, 10 mmol) and 2,2-dimethylpropanoic acid (1.53 g, 15 mmol, 1.5 eq.) were dissolved in anhydrous ethyl acetate (10 mL) under argon atmosphere. In a counter flow of argon, 61 mg (0.1 mmol, 1.0 mol %) of the [(dppe)Ru(2-methylallyl).sub.2] were added, which formed the catalyst of formula (IVa). After stirring for 24 h at 20° C., the light yellow-brown reaction mixture was concentrated under reduced pressure (rotavap, 20° C. water-bath temperature). The crude product was dried for another 2 h at 20 mbar resulting in a light brown oil. The product of formula (Ia)

##STR00025##

[0087] is obtained in a yield of 99%.

[0088] In the following table more compounds of formula (la) have been produced by the same way as in Example 1. Other reaction times and/or the reaction temperature and/or the amount of ethyl acetate (solvent) have been varied.

TABLE-US-00001 amount of Yield carboxylic acid T t ethyl acetate carboxylate (compound of formula (III) [° C.] [h] [mL] [%] 2,2-dimethylpropanoic acid 20 24 10 >99 10 24 0 >99 20 6 0 >99 30 4 0 >99 40 2 0 95

Example 2

[0089] 3-Methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)pent-1-en-4-yn-3-ol (2.18 g, 10 mmol), 2,2-dimethylpropanoic acid (1.32 g, 11 mmol) and 2,2-dimethylpropanoic anhydride (0.4 mL, 2 mmol) were dissolved in anhydrous ethyl acetate (10 mL) under argon atmosphere. In a counter flow of argon, a solution of 61 mg (0.1 mmol, 1.0 mol %) of the [(dppe)Ru(2-methylallyl).sub.2] in anhydrous acetone (5 mL) were added, which formed the catalyst of formula (IVa). After stirring for 18 h at 20° C. a conversion of 89% 3-Methyl-1-(2,6,6-trimethylcyclohex-1-en-1-yl)pent-1-en-4-yn-3-ol was observed.

[0090] In the following table more compounds of formula (Ia) have been produced by the same way as in Example 3. Other additives and/or solvent have been varied.

TABLE-US-00002 Conversion of T t formula (II) Solvent [° C.] [h] Additive [%] ethyl acetate 20 18 — 81 ethyl acetate 20 18 2,2-dimethylpropanoic 89 anhydride (2 mmol) ethyl acetate 20 18 H.sub.2O (0.5 mol %) 49 acetone 20 18 — 79 acetone 20 18 2,2-dimethylpropanoic 85 anhydride (2 mmol)

Example 3

[0091] 2,2-dimethylpropanoic acid (1.0 g, 9.8 mmol) and 60 mg (0.1 mmol) of the ruthenium catalyst of formula (IV) were dissolved in anhydrous ethyl acetate (15 mL) under argon atmosphere. After 0.5 h the solvent was evaporated for 2 hours (40° C.). The remaining solid was dissolved in anhydrous n-hexane at reflux and allowed to cool gradually from 60° C. to −20° C. for yellow sharp crystal formation to obtain the ruthenium catalyst of formula (IVb).

Example 4

[0092] 2,2-dimethylpropanoic acid (5.0 g, 49 mmol) and 60 mg (0.1 mmol) of the ruthenium catalyst of formula (IV) were dissolved in anhydrous ethyl acetate (10 mL) under argon atmosphere. After 0.5 h the solvent was evaporated for 2 hours (40 ° C.). The remaining solid was dissolved in acetone and slow diffusion of n-hexane were set up for yellow sharp crystal formation to obtain the ruthenium catalyst of formula (IVc′),