WO2019185730A1

WO2019185730A1 - Catalytic synthesis of biarylic compounds

Info

Publication number: WO2019185730A1
Application number: PCT/EP2019/057746
Authority: WO
Inventors: Dirk De Vos; Patrick Tomkins; Jannick VERCAMMEN
Original assignee: Katholieke Universiteit Leuven
Priority date: 2018-03-27
Filing date: 2019-03-27
Publication date: 2019-10-03
Also published as: GB201804905D0

Abstract

The invention relates to methods for synthesizing a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of an ordered, porous material, a catalytic transition metal and an 5 oxidant, wherein the two arene compounds can be different or identical, wherein each of the two different or wherein the identical arene compounds contains at least one H-substituent, and wherein at least one of the arene compounds or wherein the identical arenes are substituted with at least one substituent, different from H.10

Description

CATALYTIC SYNTHESIS OF BIARYLIC COMPOUNDS

FIELD OF THE INVENTION

The present invention provides a method by which aromatic compounds react towards molecules containing a biarylic moiety. This reaction is catalyzed by a transition metal, typically palladium, which is either introduced into the zeolite or related ordered, porous material prior to reaction; or both the zeolite or related ordered, porous material and the palladium are added to the reaction mixture separately. An oxidant is used to sustain the reaction. One objective of the invention is to replace homogeneous strong acid co-catalysts by the non-corrosive zeolite or related ordered, porous material. The second objective of the invention is to steer the regioselectivity of the reaction. The use of zeolites or related ordered, porous materials makes it possible to control the regioselectivity in this reaction, i.e. influence the position of the C-H bond that reacts compared to reactions without zeolite or related ordered, porous material.

BACKGROUND OF THE INVENTION

Biarylic motifs are found in specialty chemicals, e.g. in many pharmaceuticals as well as in less specialized applications, e.g. as heat transfer medium. One traditional route is the Ullmann reaction, in which aryl halides are converted to symmetric biaryls by a copper catalyst. Further, biarylic compounds can be produced by Suzuki cross-couplings. This process typically involves the reaction of a borylated arene ring with a halogenated arene ring in the presence of a palladium catalyst, both reagents being rather expensive and intrinsically producing waste. An attractive alternative is the direct conversion of the arenes to the biarylic compound by replacing a C-H bond with an arene. This method intrinsically does not produce harmful waste, as water is the only by-product, if oxygen is used as oxidant. Of the numerous publications regarding the activation of C-H groups to convert them to other groups (Liu et al. Chem. Rev. 115 (2015) 12138-12204, Gensch et al. Chem. Soc. Rev. 45 (2016) 2900-2936, Boorman and Lorrosa Chem. Soc. Rev. 40 (2011) 1910-1925 or Song et al. Chem. Soc. Rev. 41 (2012) 3651-36778), only a fraction describes the coupling of two aromatic compounds. A so far not resolved issue is the conversion of substituted aromatic compounds in a way, in which the regioselectivity is systematically controlled. Besides, there is no well-performing method, by which a corrosive liquid acid co- catalyst can be replaced by a non-corrosive solid. JP06135859 describes the utilization of solid catalysts, which are prepared by impregnation of 12 membered ring zeolites with palladium, e.g. 5 wt%, and eventually copper, usually followed by calcination. At most 3 molecules of biphenyl per atom of palladium were reported to be produced. No substituted arenes were investigated for the oxidative coupling.

JP08119883 describes the utilization of group VIII elements supported on zeolites for the dimerization of benzene. Platinum was claimed to be exceptionally effective and reaction temperatures in the range of 300 °C to 1000 °C, most preferably 400 °C - 800 °C were suggested, using an inert carrying gas, such as nitrogen or even hydrogen. No reactions of substituted aromatic compounds were described. US20140316155A1 and US2014275609A1 describe the conversion of toluene, xylenes and mixtures thereof, in which the reactant is contacted with hydrogen in the presence of a suitable hydroalkylation catalyst. The resulting products (methyl substituted cyclohexyl arenes) are subsequently dehydrogenated towards the methyl substituted biaryls.

Okamoto J. Organomet. Chem. 66 (2002) 59-65 describes the dimerization of benzene using Pd(OAc)₂, in the presence of heteropolyacids and acetic acid using oxygen at 130 °C. Phenol and phenyl acetate were observed as side-product and acetic acid was shown to be necessary for acceptable biphenyl yields. Besides the reaction of benzene, no reactions of substituted aromatic compounds were described.

Xu et al. J. Catal 187 (1999) 358-366 describes the dimerization of toluene using Pd(OAc)₂ and Pd(OTf)₂ at room temperature in the presence of dissolved triflic acid. The main product was 3,4'-dimethylbiphenyl, which was described to be the thermodynamically favoured product and was formed with selectivities of up to 58.25 % and up to 21.97 % conversion using 7.2 mol% Pd(TfO)₂.

Yokota et al. Adv. Synth. Catal. 344 (2002) 849-854 describes the homocoupling of benzene to biphenyl using Pd(OAc)₂, acetic acid and heteropolyacids at 70- 100 °C using oxygen as the sole oxidant. No substituted arenes were investigated. Liu et al ChemCatChem 8 (2016) (20-454 describes the homocoupling of benzene to biphenyl using very strong organic acids and employing a mixture of acetic acid and water, with no other substrates except for benzene reported. Pd(OAc)₂ was used as palladium source and oxygen was used as oxidant. Turnover numbers up to 180 were reported using para-toluenesulfonic acid. Other acids, such as triflic acid or methylsulfonic acid were also reported to be effective. Reactions were carried out at 105 °C. Mukhopadhyay et al. Adv. Synth. Catal. 343 (2001) 455-459 describes the homocoupling of aromatic compounds using PdCI₂ and several co-catalysts (Zr(OAc)₄, CO(OAC)2, Mn(OAc)₂ and acetylacetone) at 105 °C. Under standard reaction conditions, 7 mol% PdCI₂ were used with respect to the aromatic compound, intrinsically limiting the possible turnover number, although conversions and selectivities of ~90 % were reached. Regioselectivity was not specified.

Izawa et al. Adv. Synth. Catal. 352 (2010) 3223-3229 describes the coupling of ort/70-xylene to form 3,3',4,4'-tetramethylbiphenyl using Pd(OAc)₂, Cu(OTf)₂ in acetic acid as solvent using 2-fluoropyridine as a ligand and oxygen as oxidant. Trifluoroacetic acid was used as a strong acid co-catalyst. For ort/?o-xylene, yields up to 8 %, corresponding to a TON of 80, were reached at a chemoselectivity of 94 % and a regioselectivity towards 3,3',4,4'-tetramethylbiphenyl of 88 %. No examples of regioselective coupling of monosubstituted aromatics were given.

Kar et al. Chem. Commun. (2008) 386-388 describes the homocoupling of aromatic compounds using PhI(OAc)₂ as oxidant and HAuCU as catalyst at 55 °C or 95 °C. Strong electronically biased or sterically demanding multisubstituted aromatic compounds were employed to induce a rather regioselective reaction that prefers the reaction on a certain carbon atom in the aromatic ring. No examples of regioselective coupling of monosubstituted six-ring aromatics were given.

Liu et al. Appl. Catal., B 209 (2017) 679-688 describes the homocoupling of benzene, toluene and xylenes, in which Pd(II) was immobilized on a polymer that was prepared from maleic anhydride and 4-styrenesulfonic acid (sodium salt), which was subsequently converted to its proton form. Reactions were generally carried out in the presence of 0.036 mol% of immobilized Pd and 5.33 mol% triflic acid in a mixture of acetic acid and water at 8 atm oxygen at 120 °C. Turnover numbers up to 487 were reached and no specific regioselectivity was observed. Serna & Corma ChemSusChem 7 (2014) 2136-2141 describes the utilization of gold nanoparticles supported on titania for the homocoupling of aromatic compounds in the presence of oxygen. Turnover numbers up to 230 were reported. Besides, the formation of different regioisomers was observed and no specific regioselectivity was reported.

Mathew et al. J. Mol. Cat. A: Chem. 417 (2016) 64-70 describes the meta- selective arylation in the 3-position on the aromatic ring of pivanilide using copper- exchanged zeolites and Ph₂IOTf as arylation agent. There was no distinct difference observed, when different zeolites, such as mordenite, Y or beta were used. The reaction is also meta-selective in the absence of a zeolite, as shown in Phipps Science 323 (2009) 1593-1597.

Besides, there is a series of approaches in which regioselectivity is induced for highly specific substrates bearing a directing group, which are widely spread throughout academic literature (see e.g. Ding et al. J. Am. Chem. Soc. 139 (2017) 417-425 or Xu et al. Org. Lett. 17 (2015) 3830-3833). These approaches have the intrinsic disadvantage that only specific products can be obtained, with a strong preference for the positions ortho to the directing group substituent. In most cases these approaches are not transferable to other reactions.

The available literature clearly shows that there is a lack of control for the regioselectivity of arene-arene couplings including the C-H activation of at least one C-H bond. Further, in most cases corrosive acids are used in combination with palladium and the reaction is barely feasible without these acids.

SUMMARY OF THE INVENTION

A method for producing biphenyl and substituted derivatives comprising oxidatively coupling an arene in the presence of at least a palladium compound and a porous solid is described. In particular, a method for controlling the regioselectivity in the coupling of substituted arenes, such as toluene, is described by utilizing zeolites or related ordered, porous materials. Further, the formation of triarylic compounds is reduced.

The present invention relates to a method for the production of compounds containing at least one bond between two aromatic rings by reaction of two aromatic molecules at two carbon atoms bearing a hydrogen substituent. This reaction is made possible by utilizing a zeolite or a related ordered, porous material that is either loaded with a palladium compound prior to reaction; or the zeolite or a related ordered, porous material and the palladium compound are added separately to the reaction mixture. The reaction medium containing at least one type of arene is contacted with the palladium/zeolite or a related ordered, porous material system at temperatures between 10 °C and 300 °C. An oxidant is needed to sustain the reaction.

Thus, a first objective of the present invention is to provide a method for the formation of biarylic compounds using zeolites or related ordered, porous materials rather than homogeneous acids.

A second objective of the present invention is to provide a method for the control of regioselectivity in the coupling of substituted arenes to biphenyl derivatives. This can be achieved by choosing a suitable zeolite topology or specific related ordered, porous material for carrying out the reaction according to this invention.

The invention is summarized in the following statements:

1. A method for synthesizing a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of an ordered porous material, a catalytic transition metal and an oxidant, wherein the two arene compounds can be different or identical, wherein each of the two different or wherein the identical arene compounds contains at least one H- substituent, and wherein at least one of the arene compounds or wherein the identical arenes are substituted with at least one substituent, different from H .

2. A method for synthesizing a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of: an ordered porous material which is zeolite with between 10 to 14 membered rings, -a catalytic transition metal

- an oxidant, and

- a neutral or anionic ligand that engages in a coordinative bond with the metal via one or more oxygen, nitrogen or sulfur atoms wherein the two arene compounds can be different or identical, wherein each of the two different or wherein the identical arene compounds contains at least one H-substituent, and wherein at least one of the arene compounds or wherein the identical arenes are substituted with at least one substituent, different from H .

3. The method according to statement 2, wherein the ligand comprises a carboxyl, carboxylate, hydroxyl, carbonyl, aldehyde, alkoxy, carboxamide, amine, imine, amide, nitro, nitrate, nitrile, pyridyl, sulfide, sulfinyl, sulfonyl, sulfino, sulfo, carbothioic, phosphino, phosphono or phosphate group.

4. The method according to statement 2 or 3, wherein the ligand is selected from the group consisting of acetic acid, propionic acid, butyric acid, isobutyric acid, 2- hydroxypyridine, /V-substituted amino acids and 2-fluoropyridine.

5. The method according to any one of statements 1 to 4, wherein said ordered, porous material is a zeolite with between 10 to 14 or 10 to 12 membered rings.

6. The method according to any one of statements 1 to 5, wherein said two arene compounds are identical.

7. The method according to any one of statements 1 to 5, wherein said two arene compounds are different.

8. The method according to statement 7, wherein both of said arene compounds are substituted. 9. The method according to statement 7, wherein one of said arene compounds is substituted.

10. The method according to any one of statements 1 to 9, wherein the identical arene compounds or at least one of the different arene compounds are substituted with one or two substituents, different from H.

11. The method according to any one of statements 1 to 10, wherein said substituent is selected, independently for each of the different arene compound and for each position, from the group consisting of alkyl, alkenyl, alkynyl, alkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, alkanoyloxyalkyl, and alkyl wherein the hydrogen atom is substituted with an acetyl, halogen or nitro group.

12. The method according to any one of statements 1 to 10, wherein said substituent is selected, independently for each of the different arene compound and for each position, from the group consisting of hydroxyl, amine, amide, nitrile, halogen, phosphate and phosphonate.

13. The method according to any one of statements 1 to 5, wherein the two arene compounds are different, wherein each of the two different arene compounds contains at least one H-substituent, and wherein one of the arene compounds is substituted with one substituent, different from H.

14. The method according to statement any one of statements 1 to 13, wherein one or both arene compounds comprise an aromatic six-membered ring with or without heteroatoms or comprise a five-membered ring containing aromatic compound with or without a heteroatom.

15. The method according to statement 14, wherein both arene compounds comprise an aromatic six-membered ring.

16. The method according to statement 14 or 15, wherein one or both arene compounds comprise an aromatic six-membered ring without heteroatoms.

17. The method according to any one of statements 1 to 16, wherein one or both arene compounds comprise an aromatic six-membered ring without heteroatoms, and comprise both one substituent different from H.

18. The method according to statement 14, wherein both arene compounds comprise an aromatic five-membered ring.

19. The method according to any one of statements 1 to 16, wherein the transition metal is selected from the group of Fe, Mn, Cu, Rh, Ir, Ru, Pd, Au or Pt.

20. The method according to statement 18, wherein the transition metal is Pd.

21. The method according to any one of statements 1 to 20, wherein the reaction is carried out at a temperature of at least 10 °C up to 300 °C. 22. The method according to any one of statements 1 to 21, in which the transition metal and the ordered, porous material are added with prior loading of the transition metal onto the porous material.

23. The method according to any one of statements 1 to 21, in which the transition metal and the ordered porous material are added without prior loading of the transition metal onto the porous material.

24. The method according to any one of statements 1 to 23, in which the oxidant is oxygen.

25. The method according to any one of statements 1 to 23, in which a solid or liquid oxidant is added.

26. The method according to any one of statements 1 to 25, further comprising the step of adding a redox-active co-catalyst to the reaction mixture.

27. The method according to statement 26, wherein the redox-active co-catalyst is a transition metal or a redox-active organic compound.

28. The method according to any one of statements 1 to 27, further comprising the step of adding a solvent to the reaction mixture.

29. The method according to any one of statements 1 to 28, in which the reaction is performed in batch, semi-batch or continuous operation.

30. A method for synthesizing a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of: an ordered porous material ,

-a catalytic transition metal

- an oxidant, and

- a neutral or anionic ligand that engages in a coordinative bond with the metal via one or more oxygen, nitrogen or sulfur atoms

wherein the two arene compounds can be different or identical, wherein each of the two different or wherein the identical arene compounds contains at least one H-substituent, and wherein at least one of the arene compounds or wherein the identical arenes are substituted with at least one substituent, different from H.

31. The method according to statement 30, wherein the ligand comprises a carboxyl, carboxylate, hydroxyl, carbonyl, aldehyde, alkoxy, carboxamide, amine, imine, amide, nitro, nitrate, nitrile, pyridyl, sulfide, sulfinyl, sulfonyl, sulfino, sulfo, carbothioic, phosphino, phosphono or phosphate group.

32 The method according to statement 31, wherein the ligand is selected from the group consisting of acetic acid, propionic acid, butyric acid, isobutyric acid, 2- hydroxypyridine, /V-substituted amino acids and 2-fluoropyridine. 33. A method for synthesizing a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of: an ordered porous material which is zeolite with between 10 to 14, or 10 to 12 membered rings,

-a catalytic transition metal

- an oxidant, and

34. Use of an ordered, porous material and a catalytic transition metal as a catalyst in the synthesis of a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of an ordered, porous material, a catalytic transition metal and an oxidant, wherein the two arene compounds can be different or identical, wherein each of the two different or wherein the identical arene compounds contains at least one H-substituent, and wherein at least one of the arene compounds or wherein the identical arene are substituted with at least one substituent, different from H.

Compared with JP06135859, wherein biphenyl is made from two identical benzene molecules, the present invention prepares biarylic compounds from aromatic compounds with substituents. Surprisingly, the synthesized compounds show a high degree of regioselectivity.

Regioselectivity can be increased by using zeolites as recited in the claimed invention.

In addition the method of the present invention uses neutral or anionic ligands that engage in a coordinative bond with the metal of the catalyst via one or more oxygen, nitrogen or sulfur atoms. The addition of such compound dramatically increases the turnover number of the catalyst in the reaction (i.e. number of moles of aromatic compound converted to the biarylic compound per mole of catalyst atom). The examples section shows yields of about 200 biaryl per Pd atom compared to less than 3 as disclosed in JP06135859.

Apart from acetic acid/acetate as demonstrated in the examples, other suitable compounds such as propionic acid/propionate or butyric acid/butyrate can be used to increase the yield of the reaction. BRIEF DESCRIPTION OF THE FIGURE

Figure 1. Regioisomer distribution for different systems described in Example 4 and Comparative Example 3.1*. DETAILED DESCRIPTION OF THE INVENTION

The method disclosed in this patent provides a method for the conversion of aromatic compounds toward biphenylic compounds, which is possible at high turnover numbers and with high regioselectivity.

The method according to this invention is the transformation of an arene or a mixture of arenes to biarylic compounds in the presence of a zeolite or another ordered, porous material, and a catalytic transition metal at the reaction temperature in the presence of an oxidant. Eventually, a co-catalyst can be added with the purpose of facilitating the reoxidation of palladium or a solvent can be utilized. The reaction can be carried out in batch, semi-batch or continuous operation. The single components and specific embodiments of the method described in this invention are discussed more in detail in the following sections. The method according to this invention employs an "aromatic compound", "aromatic reactant" or "arene" as starting reagent. Such an aromatic compound is a compound containing at least one conjugated unsaturated ring. This can be a 6- ring bearing up to six substituents, of which at least one is hydrogen according to Scheme 1 ; those substituents can or cannot be connected to each other by forming or not forming an additional cyclic moiety. In an alternative embodiment of the invention, the ring consists of a 5-ring, with at least one non-carbon atom. The ring contains at least one carbon atom, although there can also be nitrogen, oxygen, sulfur or boron in the ring. R¹ to R⁵ can comprise, but are not limited to, H, C, N, O, S, F, Cl, Br, I, B, Sn, Li, Na, K. In case of certain heteroatoms (e.g. N for the 6-ring or N, O or S for the 5-ring aromatics), the R is not present for the position of the heteroatom. Examples of the rests R¹ to R⁵ include, but are not limited to alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, alkoxycarbonyl groups, aryloxycarbonyl groups, alkanoyloxy groups, alkanoyloxyalkyl groups, an alkyl group, where the hydrogen atom is substituted with an acetyl group, halogen or nitro group. Further non-limiting examples for R¹ to R⁵ are hydroxyl groups, amine groups, amides, nitriles, halogens, phosphates or phosphonates.

Specific examples of aromatic compounds include, but are not limited to benzene, toluene, ortho-xylene, meta-xylene, para-xylene, ethylbenzene, diethylbenzene isomers, styrene, n-propylbenzene, cumene, cymene isomers, durene, pyridine, methylpyridines, phthalic acid, isophthalic acid, terephthalic acid, phthalic diesters, isophthalic diesters, terephthalic diesters, 2,6-dimethylbenzyl acetate, aniline, o- chlorotoluene and trifluorotoluene. In one embodiment of the invention, only one aromatic compound is employed in the reaction. Also bi- and polycyclic compounds can potentially be applied, either as carbocyclic or heterocyclic molecules. Examples are naphthalene, tetralin, indene, indole, indoline, isoindole, (iso)benzofuran, (iso)benzothiophene, benzimidazole, aza-indole isomers, purine, benzooxazole, benzothiazole, benzoisoxazole, benzoisothiazole, quinolone, isoquinoline, phthalazine, quinoxaline, naphthyridine isomers, pteridine, chromene, isochromene isomers, anthracene, fluorene, carbazole, dibenzofuran, or dibenzothiophene, and all substituted variants of these compounds.

In an alternative embodiment of the invention, a mixture of aromatic compounds, e.g. a 6-ring and a 5-ring aromatic compound, or two different 5-ring or 6-ring aromatics are employed in the reaction.

Non-carbon

6-ring aromatic compound 5-ring aromatic compound (heterocyclic)

Scheme 1. Drawing of an aromatic compound/arene according to this invention. X can stand for, but is not limited to C, N, S, O or B, whereas at least one X is C.

The products according to this invention are "Biaryls" or "biarylic compounds". These biaryls or biarylic compounds are compounds that contain two aromatic compounds as they were defined above that are connected to each other by a single bond, as shown in

Scheme 2. These biaryls contain the same substituents as the arenes employed in the reaction, or the substituent might be modified before, during or after the reaction, e.g. by oxidation of the substituent. R¹ to R⁵ can be identical to those described for the aromatic compounds. In case of certain heteroatoms (e.g. N for the 6-ring or O for the 5-ring aromatics), the R is not necessarily present.

Scheme 2. Drawing of biaryl/biarylic compounds according to this invention. X can stand for, but is not limited, to C, N, S, O or B, whereas at least one X is C.

One objective of the present invention is the control over the formation of "regioisomers". Regioisomers are compounds with an identical atomic

composition, yet a different connectivity of one substituent to the rest of the compound. More specifically for this invention, regioisomers are compounds in which the two aromatic compounds are connected in different positions relative to the other substituent or substituents. Regioisomers are possible, if at least one monosubstituted or multisubstituted aromatic compound, which results in more than one possible product, was employed in the reaction according to this invention. Benzene or symmetrically substituted compounds, such as p-xylene cannot form several regioisomers. For example, for a monosubstituted arene, there are six different regioisomers in case of a coupling of two identical aromatic compounds and nine different products in case of a coupling of two different aromatic compounds and theoretically twelve further isomers by the coupling of two identical aromatic rings as side-product. An example of regioisomeric biarylic compounds formed from two identical arenes connected by one bond is given in

Scheme 3.

Scheme 3. Possible regioisomers formed from two identical aromatic compounds connected to each other.

Surprisingly, the inventors found, that the regioisomer distribution can be controlled by employing a zeolite or related ordered, porous material in the reaction. In prior art there is not a single example and especially no structured approach for gaining control over the regioselectivity in reactions of compounds that do not contain a directing group. The topology of the zeolite employed in the reaction directs the formation of regioisomers.

The zeolite according to this invention is a crystalline microporous aluminosilicate or silicate, which can contain extraframework cations as counterions to the framework. The cations can be present as the sole cation or as a mixture of those cations. The cations can be, but are not limited to H⁺, NH₄ ⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Fe²⁺, Fe³⁺, Mn²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Ce³⁺, Ce⁴⁺ and Y³⁺. In a preferred embodiment of this invention, H⁺, NH₄ ⁺, Na⁺, Cu²⁺, K⁺, Rb⁺, Sr²⁺ or Ba²⁺ are present in the zeolite as sole cation or as one cation in a mixture of cations. In an even more preferred embodiment of this invention, H⁺, NH₄ ⁺ or Na⁺ are present in the zeolite as sole cation or as one cation in a mixture of cations. In the most preferred embodiment of this invention, H⁺ is present in the zeolite as sole cation or as one cation in a mixture of cations.

In an alternative embodiment of the invention, not aluminum, but a different heteroatom is incorporated in the crystal lattice or a mixture of aluminum and an additional heteroatom are present in the silicate framework. The eventual counterion can be identical to those defined in the previous paragraph. This heteroatom can be, but is not limited to, B, Ga, Ge, Sn, Ti, Zr, Fe, Zn. In yet a further alternative embodiment of the invention, at least two heteroatoms which can be, but are not limited to, B, Ga, Ge, Sn, Ti, Zr are present in the S1O2- containing framework. In a preferred embodiment of this invention, B, Ga or Ge can be in the SiC>2-containing framework.

In yet a further alternative embodiment of the invention, the said porous aluminosilicates with eventual substituted cations can also contain phosphates that replace silica units, which results in aluminophosphate or silicoaluminophosphate molecular sieves.

In yet a further alternative embodiment of the invention, non-zeolite materials that are porous materials which are ordered, for example but not limited to titanosilicates (e.g. ETS-10), can be employed in the reaction.

The zeolite according to this invention, irrespective of the composition defined above, contains at least 8-membered rings or larger rings. Topologies according to the International Zeolite Association can be, but are not limited to, *BEA, BEC, *-ITN, MOR, MWW, FAU, MFI, MEL, -IFU, IRR, IWW, CHA or ERI. In a preferred embodiment of this invention, the zeolite contains 10-membered rings or larger ones. In this case, topologies according to the International Zeolite Association can be, but are not limited to, *BEA, BEC, *-ITN, FAU, MFI or MEL.

In an alternative embodiment of this invention, mixtures of materials defined in the previous paragraphs can be employed in the reaction.

In yet a further alternative embodiment of this invention, mixtures of materials defined in the previous paragraphs with non-porous materials can be employed in the reaction.

In yet a further alternative embodiment of this invention, mixtures of materials defined in the previous paragraphs with other porous materials, e.g. macroporous materials, can be employed in the reaction.

The palladium that is present in the reaction according to this invention is introduced by using a palladium precursor or elemental palladium. The palladium compounds that can be employed according to this invention can contain formally positively charged or neutral palladium. In case of formally positively charged palladium, the palladium salt according to the present invention, can be a salt of an inorganic acid with palladium. Examples can be, but are not limited to palladium halogenides, such as palladium chloride, palladium bromide or palladium iodide, palladium nitrate, tetrammine palladium nitrate, tetrammine palladium chloride, palladium hydroxide or palladium sulfate. Also, a salt of palladium with an organic acid can be used as palladium source according to the invention, where the palladium is formally positively charged. Examples can be, but are not limited to palladium acetate, palladium propionate, palladium pivalate, palladium trifluoroacetate, palladium trifluoromethanesulfonate, bis(acetylacetonato)- palladium. Examples of Pd-compounds that contain formally neutral palladium species are, but are not limited to Pd(dibenzylideneacetone)2 or Pd₂(dibenzylideneacetone)₃-CHCl₃. All these compounds can either be employed in their pure or not pure form. They can be added as solid or as solution. In a preferred embodiment of the invention, the compound is not a Pd halogenide. In an alternative embodiment of the invention, mixtures of palladium compounds can be employed.

According to the invention, palladium can be introduced into the system by loading it onto the zeolite or related ordered, porous material prior to the reactions. Any method known to those skilled in the art can be employed to do so. These methods include, but are not limited to:

(i) Ion exchange of a zeolite (H-form, NH₄-form or M-form, M being a metal cation) or related ordered, porous material with a palladium compound in aqueous media.

(ii) Loading of the zeolite or related ordered, porous material with an at least partially soluble palladium compound in an excess of non-aqueous solvent.

(iii) Wet impregnation of the zeolite or related ordered, porous material, in which the material is suspended in a Pd-containing aqueous or non-aqueous solution, followed by evaporation of the solvent.

(iv) Incipient wetness impregnation of the zeolite or related ordered, porous material, in which the eventually predried material is impregnated with an amount of a Pd-containing aqueous or non-aqueous solution that is not sufficient to form a suspension. The solvent can eventually be allowed to evaporate.

(v) Physically mixing of the zeolite or related ordered, porous material and palladium compound (e.g. by ball milling, grinding, ...).

(vi) Adding a palladium compound during the synthesis of the zeolite or related ordered, porous material.

All these approaches can or cannot be carried out multiple times and can or cannot be followed by a heat treatment.

In an alternative embodiment of this invention, palladium is brought into contact with the zeolite or related ordered, porous material prior to reaction in a suspension that is either prepared outside of the reactor in which the reaction will take place or inside the reactor in which the reaction according to this invention will take place. This suspension contains the zeolite, a palladium compound and a suitable liquid, which can be, but is not limited to, a solvent during reaction or the reacting aromatic compound. In yet a further alternative embodiment of this invention, the palladium compound is directly added before the reaction to form a suspension of at least one zeolite or related ordered, porous material, one palladium compound and one arene. This reaction mixture can be allowed to react at the desired reaction temperature.

The preferred loading of the palladium with respect to the solid is in the range of 0.001 wt% to 50 wt%, more preferably 0.1 wt% to 10 wt % and most preferably 0.5 wt% to 5 wt%.

In an alternative embodiment of this invention, not palladium but a different transition metal is employed in the reaction. This transition metal can be utilized according to the methods described for Pd, i.e. directly added to the reaction mixture or introduced into the porous material before use. In a preferred embodiment of this invention the transition metal is from group 7 to 12, as an example for the 4^th period from Mn to Zn. More preferred metals are Mn, Fe, Co, Ni, Cu, Ru, Rh, Pt, Re, Os, Ir, Pt and Au. Most preferred metals are Fe, Mn, Ni, Cu, Ru, Rh, Ir, Pt and Au. These metals can be employed in any possible oxidation state. For reasons of better readability, palladium is described throughout the document and the alternative metals are not always mentioned. However, all points of the invention are also applicable to these other transition metals.

The preferred reaction temperature according to this invention is from 10 C to 300 °C. In a preferred embodiment of this invention, the reaction temperature ranges from 40 to 250 °C. In the most preferred embodiment of this invention, the reaction temperature ranges from 60 °C to 200 °C.

According to this invention, an oxidant has to be present in the reactor to perform the reaction. This oxidant can either be of organic nature and/or it can contain a redox-active metal or metal cation or be inorganic. Examples are, but are not limited to, oxygen, meta-chloroperoxybenzoic acid or other peracids, tert-butyl hydroperoxide, benzoquinone, hydrogen peroxide or any of its adducts, N₂0, O3, hypochlorous acid, Ag₂CC>₃, Cu(OAc)₂ and its hydrates. In a preferred embodiment of the invention, the oxidant is oxygen. The preferred pressure of oxygen employed in the reaction is in the range of 0.001 bar - 1000 bar, more preferably in the range of 0.1 bar - 500 bar and most preferably in the range of 1 to 100 bar. Typically pressures below 20 bar are used.

In one embodiment of this invention, a co-catalyst is added to facilitate the reoxidation of palladium and/or influence the regioselectivity. The co-catalyst can either be added to the reaction mixture or introduced into the zeolite or related ordered, porous material with methods as they were defined for Pd above. Examples of co-catalysts are, but are not limited to inorganic compounds containing Cuⁿ⁺, Ceⁿ⁺, Feⁿ⁺, Mnⁿ⁺ and Moⁿ⁺ (n > 0) or organic redox active compounds, such as 2,2,6,6-tetramethylpiperidinyloxyl, para-quinone or anthraquinone in any reduced or oxidized form.

According to this invention, an additional solvent may be added in some cases to assure solubility of all compounds or to prevent eventual deactivation of the catalytic system, namely the zeolite and/or the palladium compound. Generally, all organic solvents can be employed in the reaction. Examples are, but are not limited to, lactones, such as gamma-v alerolactone, alkanes, such as octane or cyclohexane, organic acids, such as acetic acid, heterocycles, such as tetrahydrofuran. In a preferred embodiment of this invention, the solvent is a lactone, such as gamma-v alerolactone, an alkane, such as octane or cyclohexane or an organic acid, such as acetic acid. In an even more preferred embodiment of this invention, the solvent is an alkane, such as octane or cyclohexane or an organic acid, such as acetic acid.

The reaction can be carried out in a broad range of modes of operations. In one embodiment of the invention, the reaction can be carried out in batch, meaning that all compounds are present in the reactor and this suspension remains in the reactor during the course of the reaction. In an alternative embodiment of the invention, the reaction is carried out in semi-batch operation, in which at least one component of the reaction mixture is added during the course of the reaction; this could for example be the oxidant or the arene, but this is not a limiting description. In another embodiment of the invention, the reaction can be carried out continuously, by flowing the reaction mixture containing the reacting arene or arenes and eventual other components into a reactor or part of a reactor that is heated at the reaction temperature and contains the palladium loaded zeolite or related ordered, porous material. In an alternative embodiment of the reaction, a slurry of reacting arene or arenes, zeolite or related ordered, porous material, palladium compound and eventual further additives flow through a reactor that is heated at the reaction temperature.

This invention will now be demonstrated in more detail by examples, which it is in no means limited to. EXAMPLES

In Examples conversions and coupling yields are those of the aromatic compound towards the biarylic compounds. The TON describes the number of moles of aromatic compound converted to the biarylic compound per mole of Pd.

Products were analyzed by a Shimadzu 2010 gas chromatograph equipped with a CP-Sil 5 CB column (Agilent, 100% polydimethylsiloxane, 60 meters, 0.25 pm film thickness, 0.32 mm ID) and coupled to a flame ionisation detector (FID) that was heated at 330°C. Samples of 1 pi were injected automatically with an AOC-20s autosampler and AOC-20i auto-injector aided by the GCsolution software bundle (version 2.30.00). An injection temperature of 320°C, a split ratio of 1 :30 and N₂ as carrier gas at a constant linear velocity of 31.5 cm/s were used. The temperature of the column was kept at 50°C for 1 minute, linearly increased by 10°C/min to 320°C at which it was kept for 8 minutes. The identification of every compound was performed with GC-MS and/or by the comparison with retention times of known compounds. The final concentrations were calculated based on the peak areas of the different compounds using the effective carbon numbers for the corresponding compounds.

Conversion was calculated as: n(substrate units in products)/n(total toluene units), where n describes the amount in mol.

The Yield (Y) of the biarylic compounds was calculated as: (2x n(compound))/n(total initial amount of toluene units). The amount of product needs to be multiplied with 2, because two arene units are incorporated in the molecule. For triarylic compounds the yield was calculated as: (3x n(compound))/n(total initial amount of toluene units)

The TON was calculated as Yield(biarylic compounds)*TON at full conversion.

Example 1 - Preparation of MCM-22

For the preparation of MCM-22, NaOH (1.21 g) and Na-aluminate (1.01 g) were added to a 1 L glass beaker and distilled H₂0 (257.8 g) was added; the solution was stirred. Hexamethyleneimine (11.17 g) and aerosil 200 (19.10 g) were added. This mixture was stirred for 30 minutes. The gel was transferred to three Teflon lined autoclaves and the gel was rotated at 150°C during 200 h. The contents of the autoclaves were removed and filtered over a Buchner funnel. The filter cake was dried in an oven at 60 °C and was calcined in an oven at 580 °C until the powder was white. Subsequently the powder was refluxed for 4 h in a suspension of powder (3 g), NH₄CI (15 g, dissolved) and H₂0 (500 ml_). Afterwards, the suspension was centrifuged and calcined for 16 h at 450 °C with a heating ramp of 1 °C/min in oxygen. The resulting powder was MCM-22.

Example 2 - Preparation of B-MCM-22

Piperidine (20.66 g) and H3BO3 (13.00 g) were dissolved in water (53.28 g); subsequently Cabosil M70 (9.37 g) was added within 15 min. This mixture was stirred for 3 h. Subsequently it was transferred to an autoclave which was rotated at 170 °C at 40 rpm for 7 days. Next the solid was separated from the suspension and thoroughly washed with water. The resulting solid was dried overnight at 100 °C. The dried solid was calcined at 550 °C for 5 h at a heating rate of 1 °C/min.

Example 3 - Dealumination of zeolite Beta

Dealumination of Zeocat PB65H (Zeochem) was carried out by suspending zeolite (1 g) in nitric acid (50 ml_, 65 %) in a Schott bottle. The mixture was placed in the oven at 110 °C for 20 min. The suspension was filtered and washed until neutral. Subsequently the material was dried at 60 °C overnight and calcined in a shallow bed at 550 °C (heating rate 1 °C /min) for 3 h.

As a comparative example, the mixture was placed in the oven for 24 hours instead of 20 minutes.

Example 4 - Preparation of B-Beta

The synthesis of B-Beta was adapted from Senapati et al. J. Mater. Chem. A 2 (2014) 10470-10484. Boric acid (0.1967 g) was dissolved in an aqueous solution of tetraethylammonium hydroxide (Alfa Aesar, 35% w/w, 11.0 ml), diluted with water (8.62 ml). The solution was stirred for 30 min. Subsequently Cab-O-Sil M5 (Cabot, 2.9 g) was added within 15 min. The solution was stirred for 2 hours. Subsequently the obtained solid of comparative example 3.1 (18.0 mg) was added. The solution was stirred for 4 hours, and then transferred to a Teflon liner, which was sealed inside a stainless steel autoclave. The autoclave was placed in an oven at 150 °C for 4 days. Next the solid was separated from the suspension by filtration and thoroughly washed with water. The dried solid was calcined at 550 °C for 3 h at a heating rate of 1 °C/min. Example 5 - Preparation of Ga-Beta

The synthesis of Ga-Beta was adapted from Reddy et al. J. Incl. Phenom. Mol. Recognit. Chem. 20 (1995) 197-210. Tetraethyl orthosilicate (9.2 g) was hydrolysed in an aqueous solution of tetraethylammonium hydroxide (Alfa Aesar, 35% w/w, 10.05 g). Subsequently gallium nitrate (0.7976 g) in water (3.75 ml) and sodium hydroxide (0.2352 g) in water (2.5 ml) were added within 20 min. The mixture was stirred for 1 hour, and then transferred to a Teflon liner, which was sealed inside a stainless steel autoclave. The autoclave was placed in an oven at 140 °C for 9 days. Next the solid was separated from the suspension by filtration and thoroughly washed with water. The dried solid was calcined at 550 °C for 2 h at a heating rate of 1 °C/min. The solid was then ion exchanged three times with an aqueous solution of NH₄NO₃ (0.1 M, 100 ml/g zeolite), subsequently the material was calcined at 550 °C for 2 h at a heating rate of 1 °C/min. The material was used as such.

Example 6 - Preparation of ZSM-12

The synthesis of ZSM-12 was adapted from Section 2.2 in Okubo et al. Microporous Mesoporous Mater. 147 (2012) 149-156. Sodium hydroxide (0.0369 g) and aluminium hydroxide (Alfa Aesar, min. 76.5%, 0.0712 g) were dissolved in water (2.565 ml); subsequently an aequeous solution of tetraethylammonium hydroxide

(Alfa Aesar, 35% w/w, 3.930 ml) was added. Finally, Ludox HS-40 (4.220 ml) was added. This mixture was stirred for 30 min, and then transferred to a Teflon liner, which was sealed inside a stainless steel autoclave. The autoclave was placed in an oven at 160 °C for 5 days. Next the solid was separated from the suspension by filtration and thoroughly washed with water. The dried solid was calcined at 550 °C for 2 h at a heating rate of 1 °C/min. The solid was then ion exchanged three times with an aqueous solution of NH4NO3 (0.1 M, 100 ml/g zeolite), subsequently the material was calcined at 550 °C for 2 h at a heating rate of 1 °C/min. The material was used as such.

Example 7 - Utilization of zeolites for the coupling of toluene

Toluene (2 ml_), Pd(OAc)₂ (0.015 mmol) and the zeolite (50 mg) were added into an autoclave equipped with a glass liner that has a free volume of approx. 7 ml_. This autoclave was subsequently sealed and purged five times with approx. 20 bar oxygen and finally closed under a pressure of 16 bar oxygen. Subsequently, the autoclave was placed in a heated metal block and stirred for 16 h using a stirring bar at an internal temperature of 90°C. The solid was separated from the solution and the solution was analyzed using gas chromatrography. The results according to this invention for different commercial H-forms of zeolite beta, dealuminated zeolite beta from Example 3, Zeolite Y and the MCM-22 from Example 1 and B- MCM-22 from Example 2 are shown in Table 1. A clear dependence of the selectivity for the regioisomers on the zeolite structure could be observed and high activity (TON up to 140) is obtained. Using different zeolite beta and ZSM-12 materials, the main product is always the r,r'-bitolyl, while Zeolite Y and MCM-22 preferentially result in the formation of o,m'- and o,r'-bitolyl. Zeolites with Si/AI ratios spanning the 15-150 range were tested; several showed high activity and distinct regioisomer distributions. The B-MCM-22 material was also an active catalyst and showed similar regioselectivity as the AI-MCM-22. The regioisomer distribution for the most active systems is shown in figure 1.

Table 1. Results for the coupling of toluene using different zeolites according to this invention.

Example 8 - Homogeneous acids for the coupling of aromatic compounds (comparative example)

The procedure of Example 7 was followed, but acetic acid (1 ml.) and p- toluenesulfonic acid (0.3 mmol) were added instead of the zeolite. Acetic acid was added, because in the homogeneous case, it has been described to be necessary (cf. Liu et al. ChemCatChem 8 (2016) 448). The results for these experiments can be found in

Table 2. In contrast to Example 7, a significantly different regioisomer distribution was observed at a comparable conversion degree. The m,p' isomer was the main product, if p-toluenesulfonic acid was used. As reference, the reaction was performed with acetic acid without p-toluenesulfonic acid, p-toluenesulfonic acid without acetic acid and in the absence of any acid, which resulted in lower activity as can be seen in Table 2. These results prove that the procedure according to this invention, and as demonstrated in Example 7, employing solid zeolite acids, results in a different regioselectivity and gives a method to replace corrosive organic acids with solid acids. The regioisomer distribution is shown in figure 1. Further, more triarylic compound is formed in case of Comparative example 8 compared to the reactions shown in Example 7.

Example 9 - Reaction in the absence of Pd (comparative example)

The procedure of Example 7 was followed, but no palladium was added to the reaction mixture, as can be seen in Table 2. The reaction did not yield any product, which proves that palladium is necessary to successfully perform the reaction according to this invention.

Table 2 Results for the coupling of toluene using a strong homogeneous acid.

Example 10 - Utilization of solvents

The procedures of Example 7 were followed, except for only adding 0.5 ml. toluene and adding a solvent (2 ml) while the amount of zeolite and palladium remained the same. The reactions were carried out using zeolite beta (Zeocat PB65H, Zeochem). The results of the reactions according to this invention are summarized in Table 3 and showed lower activity than in neat toluene. However, it shows that the reaction still proceeds at considerable rate and the regioselectivity induced by the system is still present, with the r,r'-isomer being most preferred when using zeolite beta.

Table 3. Results for the coupling of toluene using different solvents according to this invention.

Example 10 - Different palladium precursors

The procedures of Example 7 were followed, except for replacing Pd(OAc)2 with an equimolar amount of another palladium precursor. The reactions were carried out using zeolite beta (Zeocat PB65H, Zeochem). The results of the reactions according to this invention are summarized in Table 4. Although a lower activity was observed than with Pd(OAc)₂, good regioselectivity was retained showing that a variety of metal precursors can be used according to this invention.

Table 4. Results for the coupling of toluene using different palladium precursors according to this invention.

Example 11 - Different oxygen pressures

The procedures of Example 7 were followed, except for varying the oxygen pressure. The reactions were carried out using zeolite beta (Zeocat PB65H, Zeochem). The results of the reactions according to this invention are summarized in Table 5. Higher oxygen pressures are beneficial within the investigated range of 1 bar 0₂ to 20 bar 0₂.

Example 12 - Different oxygen pressures (comparative example)

The procedure of Example 7 was followed, except for replacing oxygen gas with nitrogen gas. The reaction was carried out using zeolite beta (Zeocat PB65H, Zeochem). The result of the reaction is shown in Table 5. A TON of only 1 shows the necessity of oxygen to maintain a catalytic reaction.

Table 5. Results for the coupling of toluene using different oxygen pressures according to this invention.

Example 13 - Different amounts of zeolite

The procedures of Example 7 were followed, except for varying the amount of zeolite. The reactions were carried out using zeolite beta, as specified in Table 6. The results are summarized in Table 6 and show that it is possible to reach high activity over a broad range of added zeolite amounts. Table 6. Results for the coupling of toluene using different amounts of zeolite according to this invention.

Example 14 - Different temperatures

The procedures of Example 7 were followed, except for varying the temperature. The reactions were carried out using zeolite beta (Zeocat PB65H, Zeochem). The results are summarized in Table 7 and show that it is possible to reach high activity over a broad range of temperatures. Over a temperature range of 100 to 150 °C increasing TON can be observed, which are all higher than those observed at 90 °C in Example 7.

Table 7. Results for the coupling of toluene at different temperatures according to this invention.

Example 15 - Different reaction times

The procedures of Example 7 were followed, except for varying the reaction time. The reactions were carried out using zeolite beta (Zeocat PB65H, Zeochem). The results of the reaction according to the invention are shown in Table 8. With increasing reaction time the yield increases steadily and high regioselectivity towards the r,r'-bitolyl is observed.

Table 8. Results for the coupling of toluene at different reaction times according to this invention.

Example 16 - Variation of the palladium concentration at fixed Pd/zeolite ratio

The procedures of Example 7 were followed, except for varying the amount of zeolite and palladium at a constant ratio of Pd/zeolite and carrying the reaction out for only 2 h. The reactions were carried out using zeolite beta (Zeocat PB65H, Zeochem). The results of the reaction according to the invention are shown in Table 9. These results show that it is possible to employ different amounts of palladium according to this invention.

Table 9. Results for the coupling of toluene at different zeolite and palladium amounts according to this invention.

Example 17 - Palladium loading of zeolite beta

The H-form of zeolite beta (Zeocat PB65H) was loaded with palladium by suspending the solid (1 g) in a solution of palladium acetate (0.3 mmol) in toluene (100 ml.) and stirring for 24 h at room temperature. The solution became colourless during the loading, indicating high uptake of the zeolite. Subsequently the suspension was filtered and washed thoroughly with toluene and subsequently acetone.

Example 18 - Palladium exchange of zeolite beta (comparative example)

The Na-form of zeolite beta with a Si/AI ratio of 12.5 (Sudchemie, 1 g) was suspended in water (100 ml). Subsequently an aqueous tetramminepalladium(II) nitrate solution (Sigma-Aldrich, 10 % wt/wt, 0.2805 g) was added. The mixture was stirred for 24 hours, subsequently the solid was separated from the suspension and thoroughly washed with water. The resulting solid was dried overnight at 100 °C. The dried solid was calcined at 550 °C for 2 h at a heating rate of 0.5 °C/min.

Example 19 - Utilization of preloaded zeolite beta for the coupling of toluene

The procedures of Example 7 were followed, except for employing the preloaded zeolite beta from Example 17. The results are summarized in Table 10 and show that it is possible to reach high activity and regioselectivity using a preloaded zeolite beta catalyst.

Example 20 - Utilization of palladium exchanged zeolite beta for the coupling of toluene (comparative example)

The procedures of Example 19 were followed, except for employing the exchanged zeolite beta from Comparative Example 18. Acetic acid (67 pi) was added in a second experiment. The results are summarized in Table 10 and show that when the material is exchanged with palladium, little to no activity was observed. The activity can be increased drastically by addition of acetic acid. Table 10. Results for the coupling of toluene using a preloaded and exchanged Pd-zeolite beta catalyst according to this invention.

Example 21 - Utilization of zeolites for the coupling of benzene

The procedures of Example 7 were followed, except for employing benzene (2 ml.) instead of toluene. Different zeolites were used that were described before. Additionally the H-form zeolites mordenite (ZM-980, Zeocat) and ZSM-5 (Si/AI =80, Sudchemie) were employed. The results according to this invention are shown in Table 11. Activity was observed with all zeolites. No regioselectivity was observed, because of the symmetry of the reactant.

Example 22 - Utilization of a homogeneous acid for the coupling of benzene (Comparative example)

The procedures of Comparative Example 8 were followed, except for employing benzene (2 ml.) instead of toluene. The results are shown in Table 11. No regioselectivity was observed, because of the symmetry of the reactant.

Table 11. Results for the coupling of benzene using different zeolites according to this invention.

Example 23 - Utilization of zeolites for the coupling of anisole.

The procedures of Example 7 were followed, except for employing anisole (2 ml.) instead of toluene. Zeolite beta (100 mg) and Zeolite Y (50 mg) were employed in the reaction. In case of zeolite beta, a product precipitated which was identified by ^-NMR as the r,r'-regioisomer of bianisyl. The precipitated product in the reaction mixture was redissolved for analysis in 18 ml of chloroform. The results according to this invention are shown in Table 12. Isomers were separated and the right product, i.e. bianisyl, confirmed by GC-MS. The r,r'-regioisomer was clearly assigned by comparison with an authentic sample. The effect of the zeolite on the formation of specific isomers can clearly be seen. The preferential formation of the r,r'-isomer in case of zeolite beta and other isomers for zeolite Y show that the regioselectivity is determined by the zeolite for the arene-arene coupling of anisole. Only a low amount of trimer is formed (< 0.05 %). Example 24 - Addition of acetic acid in the coupling of anisole. (Comparative example)

The procedures of Example 23 were followed, except for addition of acetic acid to the reaction mixture. Zeolite beta (100 mg) was employed in the reaction. The results are shown in Table 12. A higher activity is obtained, while the regioisomer distribution was not changed.

Example 25 - Utilization of a homogeneous acid for the coupling of anisole. (Comparative example)

The procedures of Example 8 were followed, except for employing anisole (2 ml.) instead of toluene. The results are shown in Table 12. A less pronounced regioisomer distribution was obtained, which again shows that the zeolites influence the regioselectivity of the reaction. Further, significantly more trimer was formed (0.76 %).

Table 12. Results for the coupling of anisole using different zeolites according to this invention.

Example 26 - Utilization of zeolites for the coupling of o-xylene.

The procedures of Example 7 were followed, except for employing o-xylene (2 ml.) instead of toluene. Zeolite beta and Zeolite Y were employed in the reaction. The results according to this invention are shown in Table 13. Isomers were separated and confirmed by GC-MS. The effect of the zeolite on the formation of specific isomers can clearly be seen, with the preferred 3,3',4,4'-tetramethylbiphenyl isomer being formed with a selectivity of 89 % when using zeolite beta.

Comparative Example 27 - Utilization of a homogeneous acid for the coupling of o-xylene.

The procedures for Comparative Example 8 were followed, except for employing o-xylene (2 ml.) instead of toluene. The results are shown in Table 13. A different regiomer distribution compared to the other two examples shows that the zeolites have a significant influence on the regioselectivity for o-xylene. Table 13. Results for the coupling of o-xylene using different zeolites according to this invention.

Example 28 - Utilization of zeolite Y for the coupling of p-xylene

The procedures of Example 7 were followed, except for employing p-xylene (2 ml.) instead of toluene. Zeolite Y (CBV-760) was used. The results according to this invention are shown in Table 14. No regioselectivity was observed, because of the symmetry of the product.

Example 29 - Utilization of a homogeneous acid for the coupling of p- xylene (Comparative example)

The procedures for Comparative Example 8 were followed, except for employing p-xylene (2 ml.) instead of toluene. The results are shown in Table 14. A lower activity compared to Zeolite Y was observed.

Table 14. Results for the coupling of p-xylene using different zeolites according to this invention.

Example 30 - Addition of acetic acid

The procedures of Example 7 were followed, except for adding varying amounts of acetic acid. The reactions were carried out using 100 mg of zeolite beta (H-BEA SC150, Sudchemie). The results of the reactions according to this invention are summarized in Table 15. A higher activity is observed upon the addition of very small amounts of acetic acid. No significant influence of the addition of acetic acid on the regioselectivity was observed.

Table 15. Results for the coupling of toluene using different amounts of acetic acid as additive according to this invention.

Example 31 - Utilization of additives

The procedures of Example 7 were followed, except for addition of different additives. The reactions were carried out using 100 mg of zeolite beta (H-BEA SC150, Sudchemie). The results of the reactions according to this invention are summarized in

Table 16. The addition of linear, aliphatic carboxylic acids shows a beneficial effect on the activity, which decreases with an increase in chain length of the aliphatic tail. No differences in regioselectivity are observed.

Table 16. Results for the coupling of toluene using different additives according to this invention.

Claims

1. A method for synthesizing a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of: an ordered porous material which is zeolite with between 10 to 14 membered rings,

-a catalytic transition metal,

- an oxidant, and

- a neutral or anionic ligand that engages in a coordinative bond with the metal via one or more oxygen, nitrogen or sulfur atoms,

wherein the two arene compounds can be different or identical, wherein each of the two different or wherein the identical arene compounds contains at least one H-substituent, and wherein at least one of the arene compounds or wherein the identical arenes are substituted with at least one substituent, different from H .

2. The method according to claim 1, wherein the ligand comprises a carboxyl, carboxylate, hydroxyl, carbonyl, aldehyde, alkoxy, carboxamide, amine, imine, amide, nitro, nitrate, nitrile, pyridyl, sulfide, sulfinyl, sulfonyl, sulfino, sulfo, carbothioic, phosphino, phosphono or phosphate group.

3. The method according to claim 1, wherein the ligand is selected from the group consisting of acetic acid, propionic acid, butyric acid, isobutyric acid, 2-hydroxypyridine, /V-substituted amino acids and 2-fluoropyridine.

4. The method according to any one of claims 1 to 2, wherein said zeolite is a zeolite with between 10 to 12 membered rings.

5. The method according to any one of claims 1 to 4, wherein said two arene compounds are identical.

6. The method according to any one of claims 1 to 4, wherein said two arene compounds are different.

7. The method according to claim 6, wherein both of said arene compounds are substituted.

8. The method according to claim 6, wherein one of said arene compounds is substituted.

9. The method according to any one of claims 1 to 8, wherein the identical arene compounds or at least one of the different arene compounds are substituted with one or two substituents, different from H.

10. The method according to any one of claims 1 to 9, wherein said substituent is selected, independently for each of the different arene compound and for each position, from the group consisting of alkyl, alkenyl, alkynyl, alkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, alkanoyloxyalkyl, and alkyl wherein the hydrogen atom is substituted with an acetyl, halogen or nitro group.

11. The method according to any one of claims 1 to 9, wherein said substituent is selected, independently for each of the different arene compound and for each position, from the group consisting of hydroxyl, amine, amide, nitrile, halogen, phosphate and phosphonate.

12. The method according to any one of claims 1 to 4, wherein the two arene compounds are different, wherein each of the two different arene compounds contains at least one H-substituent, and wherein one of the arene compounds is substituted with one substituent, different from H.

13. The method according to claim any one of claims 1 to 12, wherein one or both arene compounds comprise an aromatic six-membered ring with or without heteroatoms or comprise a five-membered ring containing aromatic compound with or without a heteroatom.

14. The method according to claim 13, wherein both arene compounds comprise an aromatic six-membered ring.

15. The method according to claim 13 or 14, wherein one or both arene compounds comprise an aromatic six-membered ring without heteroatoms.

16. The method according to any one of claims 1 to 15, wherein one or both arene compounds comprise an aromatic six-membered ring without heteroatoms, and comprise both one substituent different from H.

17. The method according to claim 13, wherein both arene compounds comprise an aromatic five-membered ring.

18. The method according to any one of claims 1 to 16, wherein the transition metal is selected from the group consisting of Fe, Mn, Cu, Rh, Ir, Ru, Pd, Pt and Au.

19. The method according to claim 18, wherein the transition metal is Pd.

20. The method according to any one of claims 1 to 19, wherein the reaction is carried out at a temperature of at least 10 °C up to 300 °C.

21. The method according to any one of claims 1 to 20, in which the transition metal and the ordered, porous material are added with prior loading of the transition metal onto the porous material.

22. The method according to any one of claims 1 to 20, in which the transition metal and the ordered porous material are added without prior loading of the transition metal onto the porous material.

23. The method according to any one of claims 1 to 22, in which the oxidant is oxygen.

24. The method according to any one of claims 1 to 22, in which a solid or liquid oxidant is added.

25. The method according to any one of claims 1 to 24, further comprising the step of adding a redox-active co-catalyst to the reaction mixture.

26. The method according to claim 25, wherein the redox-active co-catalyst is a transition metal or a redox-active organic compound.

27. The method according to any one of claims 1 to 26, further comprising the step of adding a solvent to the reaction mixture.

28. The method according to any one of claims 1 to 27, in which the reaction is performed in batch, semi-batch or continuous operation.

29. Use of an ordered, porous material and a catalytic transition metal as a catalyst in the synthesis of a biarylic compound from two arene compounds, comprising the step of reacting said arene compounds in the presence of an ordered, porous material, a catalytic transition metal and an oxidant, wherein the two arene compounds can be different or identical, wherein each of the two different or wherein the identical arene compounds contains at least one H-substituent, and wherein at least one of the arene compounds or wherein the identical arene are substituted with at least one substituent, different from H.