Butadiene-2,3-dicarboxylic acid, derivatives

Bromovinyl)trimethylsilanc, 58, 153, 157 Butadiene-2,3-dicarboxylic acid, derivatives,... 

Pure crystalline 2,3-dicyanobutadiene has been prepared in high yield by gas-phase thermolysis of cyclobutene (2).2,8 Analogous thermolysis of derivatives of cyclobutene-1,2-dicarboxylic acid appears to represent general procedures for the synthesis of derivatives of butadiene-2,3-dicarboxylic acid of high purity.2,12 These... 

The selective hydrogenation of 1,5-cyclooctadiene (1,5-COD) and 1,5,9-cyclodode-catriene (1,5,9-CDT), cyclic oligomers of 1,3-butadiene, to the corresponding monoenes has been the subject of considerable interest, since the hydrogenation may constitute one of the steps leading to the synthesis of C8 and C12 lactams, dicarboxylic acids, and their derivatives. 

The generation of variously substituted butadienes has been accomplished via the thermal rDA reaction of substituted cyciohexene derivatives. Derivatives of 1,3-butadiene-2,3-dicarboxylic acid, which are otherwise difficuit to prepare, have been obtained by the vapor-phase pyrolysis of cyciohexene-1,2-... 

The aromatization of bicyclo[4.1.0]hept-3-enes gives access to a wide variety of cycloproparenes the substrates are readily available via Diels — Alder reaction of butadienes w ith cyclopropcnes. 1,2-Dihalo- and tetrahalocyclopropenes have been used for this purpose. In the aromatization step, it is important that the halo substituents arc located at Cl and C6 of the bicyclo[4.1. OJhept-3-ene. Halogens at C2 and C5 result in ring enlargement rather than aromatization on reaction with base. Oxidative bis-decarboxylation of bicyclo[4.1.0]hept-3-ene-l, 6-dicarboxylic acid was investigated as an alternative route to cycloproparenes however, the products were derived from carbenium ion capture after monodecarboxylation. 

As described by H. W. Sternberg [440], hydrocarboxylation of acetylenes is possible also in alkaline medium, where (Ni3(CO)8) is believed to function as the CO-donor. Thus, Sternberg obtained 25 % of trans-a-phenyl cinnamic acid besides 67 % of tetraphenyl butadiene, starting from diphenyl acetylene. Starting with octynes J. M. J. Tetteroo reported a considerably lower yield [146]. As mentioned on page 83, different reaction products are obtained with Co- or Fe-carbonyls on the one hand and Ni(CO)4 on the other hand. Contrary to nickelcarbonyl, cobaltcarbonyls are of such activity that the initially formed unsaturated acids are hydrocarboxylated a second time at the double bond. Thus, dicarboxylic acids or their derivatives are obtained by hydrocarboxylation of acetylenes with cobaltcarbonyls as catalysts [226, 388-391, 393-397, 441] (see also table 39). 

Hydroxycarbonylation and alkoxycarbonylation of alkenes catalyzed by metal catalyst have been studied for the synthesis of acids, esters, and related derivatives. Palladium systems in particular have been popular and their use in hydroxycarbonylation and alkoxycarbonylation reactions has been reviewed.625,626 The catalysts were mainly designed for the carbonylation of alkenes in the presence of alcohols in order to prepare carboxylic esters, but they also work well for synthesizing carboxylic acids or anhydrides.137 627 They have also been used as catalysts in many other carbonyl-based processes that are of interest to industry. The hydroxycarbonylation of butadiene, the dicarboxylation of alkenes, the carbonylation of alkenes, the carbonylation of benzyl- and aryl-halide compounds, and oxidative carbonylations have been reviewed.6 8 The Pd-catalyzed hydroxycarbonylation of alkenes has attracted considerable interest in recent years as a way of obtaining carboxylic acids. In general, in acidic media, palladium salts in the presence of mono- or bidentate phosphines afford a mixture of linear and branched acids (see Scheme 9). 

Insertion of carbon dioxide is also possible. For example, seven-mem-bered ring nickelacycle 11, derived from 1,3-butadiene, undergoes further carboxylation in the presence of pyridine to form a nickel(II) dicarboxylate complex 48, which yields a diester after treatment with methanol under acidic conditions (Eq. 20). ° Similar results are obtained in the carboxylation of (r) -diene)iron(0) complexes. ... 

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