Process for preparing substituted biphenyls via Suzuki coupling of aryl-chlorides

A process for preparing a substituted biphenyls biphenyl of the formula I

• in which the substituents are each defined as follows:
• R1 is cyano, nitro, F, Cl, C1-C4-alkyl, C1-C4-haloalkyl, C3-C10-cycloalkyl which may carry 1, 2, 3 or 4 C1-C4-alkyl substituents;
• C3-C10-halocycloalkyl, C1-C6-alkoxy, C1-C6-haloalkoxy, C1-C6-alkylcarbonyl, C1-C6-haloalkylcarbonyl, C1-C6-alkoxycarbonyl, or C1-C6-haloalkoxycarbonyl;
• R2 is cyano, nitro, F, Cl, C1-C4-alkyl, C1-C4-haloalkyl, C3-C10-cycloalkyl which may carry 1, 2, 3 or 4 C1-C4-alkyl substituents;
• C3-C10-halocycloalkyl, C1-C6-alkoxy, C1-C6-haloalkoxy, C1-C6-alkylcarbonyl, C1-C6-haloalkylcarbonyl, C1-C6-alkoxycarbonyl, or C1-C6-haloalkoxycarbonyl;
• and
• n is 0, 1, 2, or 3, where, in case that n is 2 or 3, the R1 radicals may have identical or different definitions;
• and
• m is 0, 1, 2, or 3, where, in case that n is 2 or 3, the R2 radicals may have identical or different definitions
• which comprises reacting a compound of formula II
• in which R1 and n is as defined as above,
• in the presence of a base and a palladium catalyst, where the palladium catalyst is introduced into the reaction in the form of
• a palladium source and a phosphorus ligand of formula III or a salt thereof
• in which
• R3 is C3-C18-alkyl or C3-C10-cycloalkyl which is connected to the phosphor atom at a secondary or tertiary carbon atom of the C3-C18-alkyl or C3-C10-cycloalkyl substituent;
• R4 is C1-C18-alkyl or C3-C10-cycloalkyl;
• and R5 is C1-C18-alkyl or C3-C10-cycloalkyl;
• or
• a palladium complex containing at least one phosphorus ligand of the formula III as defined above or a salt thereof;
• with water as solvent, wherein a total solvent comprises at least 95 wt.-% water based on the total solvent without the use of an additional surfactant or phase transfer catalyst
• with an organoboron compound of formula IV
• wherein R2 and m are as defined as above and the compound of formula IV is selected from the group consisting of
• (i) boronic acids with o=0, p=2;
• q=1 and Z=hydroxyl groups, or their trimers;
• (ii) boronic acid derivates with o=0, p=2;
• q=1 and Z=halogen;
• C1-C4-alkyl, C1-C6-alkoxy or C6-C10-aryloxy;
• (iii) boronic acids or boronic acid derivatives with o=0, p=1;
• q=2 and Z=hydroxy, halogen, C1-C4-alkyl, C1-C6-alkoxy or C6-C10-aryloxy;
• (iv) mixed boronic acids or boronic acid derivatives with 0=1, p=1;
• q=1, A=C1-C4-alkyl and Z=hydroxy, halogen, C1-C4-alkyl, C1-C6-alkoxy or C6-C10-aryloxy;
• (v) cyclic boronic esters with o=0, p=2 and q=1, wherein the two Z groups form together a bridging group —O—(CH2)r-O—, wherein r is 2 or 3, so that the two Z groups, together with the boron atom to which they are attached, form a 5- or 6-membered ring, where the CH2 groups are optionally substituted by one or two C1-C4-alkyl groups;
• (vi) boronates with o=0, p=3, q=1 and Z=hydroxyl, halogen, C1-C4-alkyl, C1-C6-alkoxy or C6-C10-aryloxy, and accompanied by a cation which compensates the negative charge of the boronate anion;
• (vii) triarylboranes with o=0, p=0 and q=3;
• (viii) tetraarylborates with o=0, p=0 and q=4, and accompanied by a cation which compensates the negative charge of the borate anion;
• and
• where the reaction is carried out at a temperature of from 60 to 150° C.