25569-80-6Relevant articles and documents
Palladium-catalysed synthesis of nonsymmetrically disubstituted-1,1′- biphenyls from o-substituted aryl iodides through aryl coupling and delayed hydrogenolysis
Deledda, Sara,Motti, Elena,Catellani, Marta
, p. 741 - 747 (2005)
In the presence of Pd(OAc)2 and norbornene as catalysts, two molecules of an ortho-substituted aryl iodide undergo aryl-aryl coupling to a palladium-bonded biphenylyl intermediate, which is hydrogenolyzed by benzyl alcohol to give 2,3′-disubsti
Vapour-phase Chemistry of Arenes. Part 13. Reactivity and Selectivity in the Gas-phase Reactions of Hydroxyl Radicals with Monosubstituted Benzenes at 563 K
Mulder, Peter,Louw, Robert
, p. 1167 - 1174 (2007/10/02)
The reactions of hydroxyl radicals with benzene derivates C6H5Z (Z = H, Me, F, Cl, Br, I, CF3, or CN) have been studied in a flow reactor at 563 K in nitrogen, using the thermolysis of ButOOH as a source of .OH.Under these conditions there are two product-forming pathways.The major one involves hydrogen abstraction to give aryl radicals ZC6H4. (II) as the first step; depending on Z, its displacement to form phenol may also occur.Relative rates for hydrogen abstraction were determined in competition experiments using side-chain hydrogen abstraction from added toluene as a reference.This resulted in the order (for Z =): 1,8(Me), 1.0(H), 0.47(F), 0.29(Cl), 0.34(CF3), 0.20(CN), consonant with the electrophilic nature of .OH.The site selectivity of hydrogen abstractions was determined by scavenging part of the aryl radicals (II) with iodine.A Hammett plot, using ? constants for meta and para positions, led to ρ -1.0.The features of hydrogen abstraction by .OH are discussed and compared with those for the analogous reaction of Cl.The formation of phenol was found to decrease in importance in the order F, Cl, Br, and I.This result is rationalized on a thermochemical kinetic basis.
PALLADIUM(II)-CATALYZED OXIDATIVE COUPLING OF ARENES BY THALLIUM(III)
Yatsimirsky, Anatoly K.,Deiko, Sergei A.,Ryabov, Alexander D.
, p. 2381 - 2392 (2007/10/02)
Oxidation of benzenes with electron-donating and moderate electron-withdrawing substituents by thallium(III) trifluoroacetate in the presence of catalytic amounts of palladium(II) acetate affords biaryls in good yields.The GLC study of the isomer distribution has shown that 4,4'-biaryls are the major products.Thus, the 4,4'-biaryls can be easily isolated either by recrystallization or column chromatography.The competitive experiments and kinetic study using arenes and arylthallium derivatives as starting materials as well as quenching experiments have demonstrated the first step of the reaction to be fast thallation of arene to form arylthallium intermediate ArTl(OOCCF3)2.The latter undergoes the rate-determining transmetallation step reacting with monomeric complex Pd(OAc)2, which is formed upon depolymerization of trimer Pd3(OAc)6.Subsequent fast decomposition of arylpalladium species gives the final reaction products.The thallation of arene and substitution of TlIII for PdII in ArTl(OOCCF3)2 are characterized by the slopes of Hammet plots of -5.6 (?+) and -3.0 (?), respectively.
