Ferrocene-based compounds and palladium catalysts based thereon for the alkoxycarbonylation of ethylenically unsaturated compounds

1. Compound of formula (I)

where

R 1 , R 2 , R 3 , R 4 are each independently selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —(C 6 -C 20 )-aryl, —(C 3 -C 20 )-heteroaryl;

at least one of the R 1 , R 2 , R 3 , R 4 radicals is a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms;

and

R 1 , R 2 , R 3 , R 4 , if they are —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —(C 6 -C 20 )-aryl, —(C 3 -C 20 )-heteroaryl or —(C 6 -C 20 )-heteroaryl, may each independently be substituted by one or more substituents selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —O—(C 1 -C 2 )-alkyl, —O—(C 1 -C 12 )-alkyl-(C 6 -C 20 )-aryl, —O—(C 3 -C 12 )-cycloalkyl, —S—(C 1 -C 12 )-alkyl, —S—(C 3 -C 12 )-cycloalkyl, —COO—(C 1 -C 12 )-alkyl, —COO—(C 3 -C 12 )-cycloalkyl, —CONH—(C 1 -C 12 )-alkyl, —CONH—(C 3 -C 12 )-cycloalkyl, —CO—(C 1 -C 12 )-alkyl, —CO—(C 3 -C 12 )-cycloalkyl, —N—[(C 1 -C 12 )-alkyl] 2 , —(C 6 -C 20 )-aryl, —(C 6 -C 20 )-aryl-(C 1 -C 12 )-alkyl, —(C 6 -C 20 )-aryl-O—(C 1 -C 12 )-alkyl, —(C 3 -C 20 )-heteroaryl, —(C 3 -C 20 )-heteroaryl-(C 1 -C 12 )-alkyl, —(C 3 -C 20 )-heteroaryl-O—(C 1 -C 12 )-alkyl, —COOH, —OH, —SO 3 H, —NH 2 , halogen.

2. Compound according to claim 1 ,

where at least two of the R 1 , R 2 , R 3 , R 4 radicals are a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms.

3. Compound according to claim 1 ,

where the R 1 and R 3 radicals are each a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms.

4. Compound according to claim 1 ,

where the R 1 and R 3 radicals are each a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms;

R 2 is —(C 6 -C 20 )-heteroaryl having at least six ring atoms or is selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 2 )-heterocycloalkyl, —(C 6 -C 20 )-aryl;

and R 4 is selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —(C 6 -C 20 )-aryl.

5. Compound according to claim 1 ,

where the R 1 and R 3 radicals are each a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms;

and R 2 and R 4 are selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —(C 6 -C 20 )-aryl.

6. Compound according to claim 1 ,

where the R 1 and R 3 radicals are each a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms;

and R 2 and R 4 are —(C 1 -C 12 )-alkyl.

7. Compound according to claim 1 ,

where R 1 , R 2 , R 3 , R 4 , if they are a heteroaryl radical, are each independently selected from pyridyl, pyridazinyl, pyrimidyl, pyrazinyl, benzofuranyl, indolyl, isoindolyl, benzimidazolyl, quinolyl, isoquinolyl.

8. Compound according to claim 1 ,

of one of the formulae (8), (14) and (15)

9. Complex comprising Pd and a compound according to claim 1 .

10. Process comprising the following process steps:

a) initially charging an ethylenically unsaturated compound;

b) adding a compound of formula (I)

where

R 1 , R 2 , R 3 , R 4 are each independently selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 2 )-heterocycloalkyl, —(C 6 -C 20 )-aryl, —(C 3 -C 20 )-heteroaryl;

at least one of the R 1 , R 2 , R 3 , R 4 radicals is a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms;

and

R 1 , R 2 , R 3 , R 4 , if they are —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —(C 6 -C 20 )-aryl, —(C 3 -C 20 )-heteroaryl or —(C 6 -C 20 )-heteroaryl, may each independently be substituted by one or more substituents selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —O—(C 1 -C 12 )-alkyl, —O—(C 1 -C 12 )-alkyl-(C 6 -C 20 )-aryl, —O—(C 3 -C 12 )-cycloalkyl, —S—(C 1 -C 12 )-alkyl, —S—(C 3 -C 12 )-cycloalkyl, —COO—(C 1 -C 12 )-alkyl, —COO—(C 3 -C 2 )-cycloalkyl, —CONH—(C 1 -C 12 )-alkyl, —CONH—(C 3 -C 12 )-cycloalkyl, —CO—(C 1 -C 12 )-alkyl, —CO—(C 3 -C 12 )-cycloalkyl, —N—[(C 1 -C 12 )-alkyl] 2 , —(C 6 -C 20 )-aryl, —(C 6 -C 20 )-aryl-(C 1 -C 12 )-alkyl, —(C 6 -C 20 )-aryl-O—(C 1 -C 12 )-alkyl, —(C 3 -C 20 )-heteroaryl, —(C 3 -C 20 )-heteroaryl-(C 1 -C 12 )-alkyl, —(C 3 -C 20 )-heteroaryl-O—(C 1 -C 12 )-alkyl, —COOH, —OH, —SO 3 H, —NH 2 , halogen and a compound comprising Pd,

or adding a complex according to claim 9 ;

c) adding an alcohol;

d) feeding in CO;

e) heating the reaction mixture, with conversion of the ethylenically unsaturated compound to an ester.

11. Process according to claim 10 ,

wherein the ethylenically unsaturated compound is selected from ethene, propene, 1-butene, cis- and/or trans-2-butene, isobutene, 1,3-butadiene, I-pentene, cis- and/or trans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, hexene, tetramethylethylene, heptene, I-octene, 2-octene, di-n-butene, and mixtures thereof.

12. Process according to claim 10 ,

wherein the compound comprising Pd in process step b) is selected from palladium dichloride, palladium(II) acetylacetonate, palladium(II) acetate, dichloro(1,5-cyclooctadiene)palladium(II), bis(dibenzylideneacetone)palladium, bis(acetonitrile)dichloropalladium(II), palladium(cinnamyl) dichloride.

13. Process according to claim 10 ,

wherein the alcohol in process step c) is selected from methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, tert-butanol, 3-pentanol, cyclohexanol, phenol, and mixtures thereof.

14. A process for preparing an alkoxycarbonylation reaction medium, comprising preparing the medium by introducing to a medium, a compound of formula (I)

where

R 1 , R 2 , R 3 , R 4 are each independently selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —(C 6 -C 20 )-aryl, —(C 3 -C 20 )-heteroaryl;

at least one of the R 1 , R 2 , R 3 , R 4 radicals is a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms;

and

R 1 , R 2 , R 3 , R 4 , if they are —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —(C 6 -C 20 )-aryl, —(C 3 -C 20 )-heteroaryl or —(C 6 -C 20 )-heteroaryl, may each independently be substituted by one or more substituents selected from —(C 1 -C 12 )-alkyl, —(C 3 -C 12 )-cycloalkyl, —(C 3 -C 12 )-heterocycloalkyl, —O—(C 1 -C 12 )-alkyl, —O—(C 1 -C 12 )-alkyl-(C 6 -C 20 )-aryl, —O—(C 3 -C 12 )-cycloalkyl, —S—(C 1 -C 12 )-alkyl, —S—(C 3 -C 12 )-cycloalkyl, —COO—(C 1 -C 12 )-alkyl, —COO—(C 3 -C 2 )-cycloalkyl, —CONH—(C 1 -C 12 )-alkyl, —CONH—(C 3 -C 12 )-cycloalkyl, —CO—(C 1 -C 12 )-alkyl, —CO—(C 3 -C 12 )-cycloalkyl, —N—[(C 1 -C 12 )-alkyl] 2 , —(C 6 -C 20 )-aryl, —(C 6 -C 20 )-aryl-(C 1 -C 12 )-alkyl, —(C 6 -C 20 )-aryl-O—(C 1 -C 12 )-alkyl, —(C 3 —C 20 )-heteroaryl, —(C 3 -C 20 )-heteroaryl-(C 1 -C 12 )-alkyl, —(C 3 -C 20 )-heteroaryl-O—(C 1 -C 12 )-alkyl, —COOH, —OH, —SO 3 H, —NH 2 , halogen or a complex according to claim 9 .

15. The compound of claim 1 , wherein R 1 , R 2 , R 3 , R 4 are each independently selected from —(C 1 -C 8 )-alkyl, —(C 3 -C 8 )-cycloalkyl, —(C 3 -C 8 )-heterocycloalkyl, —(C 6 -C 14 )-aryl, or —(C 6 -C 14 )-heteroaryl.

16. The compound of claim 1 , wherein at least one of the R 1 , R 2 , R 3 , R 4 radicals is a —(C 6 -C 14 )-heteroaryl radical having at least six ring atoms.