Diphenyl acetic acid, pyrolysis

Photolysis of carbethoxymethylenetriphenylphosphine in cyclohexene yields benzene, ethyl acetate, ethyl cyclohexylacetate, ethyl cyclohex-2-ene-l-acetate, phenylcyclohexane l,T-bicyclohex-2-ene (Quantum yield measured by use of a low pressure mercury lamp as a light source no yield in material) and diphenyl phosphinic acid. In this case, no triphenylphosphine is produced. On the other hand, pyrolysis of this carbethoxymethy-lene compound shows that only P=C bond fission occurs91. Using acetylmethylene-triphenylphosphine, the observed products are analogous20. However, the irradiation of... 

Pyrolysis of tri-, tetra-, and penta-chlorobenzenes affords mixtures of chlorinated dibenzofurans and dibenzo-p-dioxins, " and chlorinated diphenyl ethers cyclize in the presence of palladium acetate to polychloro-dibenzofurans/ The action of malononitrile on tetrahydroxy-p-benzoquinone leads to the benzo-difuran (79), contrary to a previous report/ The acid-catalysed condensation of quinones with phenols has been studied p-benzoquinone and resorcinol, for example, afford compound (80)/ Naphtho[2,3- >]furan-4,9-diones (81 R = Me or Ph R = Ac, Bz, C02Et, or CN) are obtained from 2,3-dichloronaphtho-1,4-quinone and compounds R COCHaR in DMF that contains potassium fluoride/ The action of mineral acids on p-benzoquinone produces a mixture of complex benzofurans, which includes (82) and (83)/ Bases convert the ben-zofuranone (84) into the tetrameric compound (85), contrary to an earlier... 

Pyrolysis of sulfoxides provides a convenient method for introducing unsaturation at the position a- to carbonyl compounds. Formation of the enolate and reaction with dimethyl (or diphenyl) disulfide gives the a-methylthio (or phenylthio) derivative. Oxidation with a suitable oxidant, such as mCPBA or NaI04, gives the sulfoxide, which eliminates sulfenic acid on heating to give the a,(3-unsaturated carbonyl compound. For example, the methyl ester of a pheromone of queen honey bees was synthesized from methyl 9-oxodecanoate after initial protection of the ketone as the acetal (2.24). The -isomer usually predominates in reactions... 

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