54576-13-5

The dicarbonylation of 1,3-butadiene to adipic acid derivatives offers the potential for a more cost-efficient and environmentally benign industrial process. However, the complex reaction network of regioisomeric carbonylation and isomerization pathways, make a selective and direct transformation particularly difficult. Here, we report surprising solvent effects on this palladium-catalysed process in the presence of 1,2-bis-di-tert-butylphosphin-oxylene (dtbpx) ligands, which allow adipate diester formation from 1,3-butadiene, carbon monoxide, and methanol with 97 % selectivity and 100 % atom-economy under scalable conditions. Under optimal conditions a variety of di- and triesters from 1,2- and 1,3-dienes can be obtained in good to excellent yields.

The invention relates to a method comprising the method steps of: a) initially charging a diene having two conjugated double bonds;b) adding a phosphine ligand and a catalyst precursor selected from palladium dichloride, palladium dibromide, palladium diiodide, palladium(II) acetylacetonate, palladium(II) acetate, bis(dibenzylideneacetone)palladium, bis(acetonitrile)dichloropalladium(II), palladium (cinnamyl) dichloride;c) adding an alcohol;d) feeding in CO;d) heating the reaction mixture, with conversion of the diene to a di- or tricarboxylic ester; wherein the phosphine ligand is a compound according to formula (I) where R1, R2, R3, R4 are selected from —(C1-C12)-alkyl, —(C6-C20)-aryl, —(C3-C12)-cycloalkyl, —(C3-C12)-heterocycloalkyl, —(C3-C20)-heteroaryl;R5, R6 are selected from —H, —(C1-C12)-alkyl, —(C6-C20)-aryl, —(C3-C12)-cycloalkyl, —(C3-C12)-heterocycloalkyl, —(C3-C20)-heteroaryl;and R1, R2, R3, R4, R5, R6, in the case that these are —(C1-C12)-alkyl, —(C6-C20)-aryl, —(C3-C12)-cycloalkyl, —(C3-C12)-heterocycloalkyl or —(C3-C20)-heteroaryl, may be each substituted independently of one another by one or more substituents selected from —(C1-C12)-alkyl, —(C3-C12)-cycloalkyl, —(C3-C12)-heterocycloalkyl, —O—(C1-C12)-alkyl, —O—(C1-C12)-alkyl-(C6-C20)-aryl, —O—(C3-C12)-cycloalkyl, —S—(C1-C12)-alkyl, —S—(C3-C12)-cycloalkyl, —COO—(C1-C12)-alkyl, —COO—(C3-C12)-cycloalkyl, —CONH—(C1-C12)-alkyl, —CONH—(C3-C12)-cycloalkyl, —CO—(C1-C12)-alkyl, —CO—(C3-C12)-cycloalkyl, —N—[(C1-C12)-alkyl]2, —(C6-C20)-aryl, —(C6-C20)-aryl-(C1-C12)-alkyl, —(C6-C20)-aryl-O—(C1-C12)-alkyl, —(C3-C20)-heteroaryl, —(C3-C20)-heteroaryl-(C1-C12)-alkyl, —(C3-C20)-heteroaryl-O—(C1-C12)-alkyl, —COOH, —OH, —SO3H, —NH2, halogen.

Reaction of cycloalkanones with [hydroxy(2,4-dinitrobenzenesulfonyloxy)iodo]benzene and subsequent treatment of α-[(2,4-dinitrobenzene)sulfonyl]oxy cycloalkanone intermediates with Oxone and PTSA in MeOH-H2O (6:1, v/v) solution provided dicarboxylic acid dimethyl esters in high yields.

α,ω-Dicarboxylic acid dimethyl esters arc easily obtained by ring cleavage of α-nitrocycloalkanones. Thus, reaction of the latter compounds with three equivalents of potassium persulfate, in methanol and in presence of sulfuric acid at 80 °C, provides α,ω-dicarboxylic acid dimethyl esters in high yields. Long-chain, and alkylated α,ω-dicarboxylic acid dimethyl esters can be also efficiently obtained.