Diphenylsuccinic acid

Compounds containing carboxyl groups on adjacent carbons (succinic acid derivatives) can be bisdecarboxylated with lead tetraacetate in the presence of O2 263 jjjg reaction is of wide scope. The elimination is stereoselective, but not stereospecific (both meso- and dl- 2,3-diphenylsuccinic acid gave trans- stilbene) a concerted mechanism is thus unlikely. The following mechanism is not inconsistent with the data ... 

Electrolysis of benzalacetophenone in the presence of C02 gave a-phenylben-zoylpropionic acid 306 Reduction of stilbene in the presence of C02 yielded 92% meso-2,3-diphenylsuccinic acid 307 The reduction of anthracene at -2,3 V in the presence of S02 and 02 yields 9,10-dihydroanthracene-9,10-disulfonic acid 307a) An interesting intramolecular addition was found in the reduction of the thiocyanato steroid 77 to the mercaptoimine 78 308 ... 

Diphenylsuccinic acids, 556 Diphenyl sulfide, 1122 Diphenyl sulfoxide, 348 Diphenyltelluride, 348-349 Diphenyltin, 349... 

Methyl acrylate [30,31], methyl methacrylate and acrylonitrile [31,33] can be dicarboxylated with yields up to 60 %. The electrocarboxyla-tive dimerization of methyl acrylate leads to 1,1,4,4-tetracarboxy-butane. Dicarboxylation of stilbenes yields 2,3-diphenylsuccinic acid [33,34]. Styrene can be carboxylated to 2-phenylsuccinic acid or to 3-phenylpropionic acid [35] and ethene reacts to succinic acid [36]... 

The electrocarboxylation of an alkyne was reported by Wawzonek [98]. The reaction of diphenyl acetylene with carbon dioxide leads to a mixture of meso diphenylsuccinic acid, fumaric acid and maleic anhydride with an overall yield of 40 %. 

Diphenylsuccinic acid, A43.7, X"7 6-Benzyloxycoumaran-2-carboxylic acid, Y1.12 6,6 -Dimethyl-2,2 -diphenic acid, X5.8... 

This also follows from the results obtained by Koehl [98]. In the oxidation of monoesters of methylpropylmalonic and methyl-isopropylmalonic acids Eberson [93] obtained a mixture of the diastereoisomers of Q, Q -dimethyl-Q, o -dipropylsuccinic and dimethyl-Q, Q -diisopropylsuccinid acids. During electrolytic oxidation of meso- and racemic 2,3-diphenylsuccinic acids in a mixture of pyridine and water (9 1) Corey and Casanova [94] obtained only trans-stilbene, which is also formed in the oxidation of these acids by lead tetraacetate. It is pointed out that these results exclude the possibility of cis-elimination. In the case of anodic oxidation of butylboric acid Humphrey and Williams [96] found that a mixture of 1-butene, cis-2-butene, and trans-2-butene in the proportions 3.3 1 1 was formed at a platinum electrode in aqueous alkaline solutions at low current densities. 

These results show that reduction of the multiple bonds takes place through trans-addition. By reduction of diphenylacetylene in dimethylformamide in the presence of carbon dioxide Wawzonek and Wearring [103] obtained diphenylfumaric acid, diphenylmaleic anhydride and meso-diphenylsuccinic acid in the proportions 2,5 1 7. If it is assumed that the meso acid is formed from fumaric acid, these results demonstrate the stereospecificity of the process, contrary to the assertions made by Wawzonek and Wearring [103], From phenanthrene in the presence of carbon dioxide they obtained trans- 9,10-dihydrophenanthrene-9,10-dicarboxylic acid. 

Recently Peover [104] has again investigated the reduction of unsaturated compounds in aprotic solvents in the presence of carbon dioxide. The meso- and racemic-diphenylsuccinic acids which he obtained in the reduction of trans- and cis-stilbenes, respectively, provide direct evidence of the stereospecificity of the process. 

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