Method for producing substituted biphenyls

1. A process for preparing substituted biphenyls of the formula I

in which the substituents are defined as follows:

R 1 is nitro, amino or NHR 3 ,

R 2 is halogen,

R 3 is C 1 -C 4 -alkyl, C 2 -C 4 -alkenyl or C 2 -C 4 -alkynyl,

m is 1 or 2, where, in the case that m =2, the two R 1 radicals may have different definitions,

n is 1, 2 or 3, where, in the case that n =2 or 3, the two R 2 radicals may have different definitions,

which comprises reacting a compound of the formula II

in which Hal is halogen and R 1 and m are each as defined above, in the presence of a base and of a palladium catalyst selected from the group of: a) palladium-triarylphosphine or palladium-trialkylphosphine complex with palladium in the zero oxidation state, b) salt of palladium in the presence of triarylphospine or trialkylphosphine as a complex ligand or c) metallic palladium,

in the presence of triarylphosphine or trialkylphosphine, in a solvent, with a diphenylborinic acid (III)

in which R 2 and n are each as defined above, where the triarylphosphines or trialkylphosphines used may be substituted.

2. The process according to claim 1 , wherein the compound (II) used is 2-nitrochlorobenzene.

3. The process according to claim 1 , wherein the starting compound (III) is a diphenylborinic acid which is substituted only in the 4-position.

4. The process according to claim 1 , wherein a diphenylborinic acid (III) is used which bears, as the sole substituent in the 4-position, fluorine, chlorine or a methyl group.

5. The process according to claim 1 , wherein the starting compound (III) is di(4-chlorophenyl)borinic acid.

6. The process according to claim 1 , wherein the palladium catalyst a) used is tetrakis(triphenylphosphine)palladium or tetrakis(tri-tert-butylphosphine) palladium.

7. The process according to claim 1 , wherein a palladium catalyst b) is used.

8. The process according to claim 7 , wherein the salt of the palladium catalyst b) used is palladium chloride, palladium acetate or bisacetonitrilepalladium chloride.

9. The process according to claim 7 , wherein a palladium catalyst b) is used for which from 6 to 60 equivalents of triphenylphosphine are used per equivalent of the palladium salt.

10. The process according to claim 1 , wherein from 0.001 to 1.0 mol % of the palladium catalyst is used, based on the compound (II).

11. The process according to claim 1 , wherein the reaction is carried out at a temperature of from 50 to 120° C.

12. The process according to claim 1 , wherein the reaction is carried out in a mixture of water and an organic solvent.

13. The process according to claim 3 , wherein the organic solvent used is an ether.

14. The process according to claim 1 , wherein the reactions are carried out at a pressure of from 1 to 6 bar.

15. The process according to claim 2 , wherein the starting compound (III) is a diphenylborinic acid which is substituted only in the 4-position.

16. The process according to claim 2 , wherein a diphenylborinic acid (III) is used which bears, as the sole substituent in the 4-position, fluorine, chlorine or a methyl group.

17. The process according to claim 2 , wherein the starting compound (III) is di(4-chlorophenyl)borinic acid.

18. The process according to claim 2 , wherein the palladium catalyst a) used is tetrakis(triphenylphosphine)palladium or tetrakis(tri-tert-butylphosphine)palladium.

19. The process according to claim 3 , wherein the palladium catalyst a) used is tetrakis(triphenylphosphine)palladium or tetrakis(tri-tert-butylphosphine)palladium.

20. The process according to claim 1 , wherein the palladium c) is used and is metallic palladium applied to a support in the presence of triarylphosphine or trialkylphosphine.

21. The process according to claim 20 , wherein the palladium catalyst c) used is metallic palladium on activated carbon in the presence of triphenylphosphine whose phenyl groups are substituted by a total of from 1 to 3 sulfonate groups.