Palladium(0) Complex-Catalyzed Debrominative Coupling of (Tribromomethyl)- and (Dibromomethyl)benzenes to Diarylacetylenes and 1,2-Diarylethenes
作者:Shuntaro Mataka、Guo-Bin Liu、Masashi Tashiro
DOI:10.1055/s-1995-3878
日期:1995.2
Palladium(0)-triphenylphosphine complex-catalyzed debrominative coupling reaction of (tribromomethyl)benzenes gave diarylacetylenes or a mixture of (E)- and (Z)-α,β-dibromostilbenes depending upon the substrate and the solvent being used. On the other hand, (dibromomethyl)benzenes afforded (E)-stilbenes selectively under the same reaction conditions.
Catalytic halodefluorination of aliphatic carbon–fluorine bonds
作者:Kelvin K. K. Goh、Arup Sinha、Craig Fraser、Rowan D. Young
DOI:10.1039/c6ra09429e
日期:——
A variety of halosilanes, in conjunction with aluminum catalysts, convert fluorocarbons into higher halocarbons. Bromination and iodination of fluorocarbons are more effective than chlorination in terms of yield and activity....
Base-Promoted Synthesis of 2-Aryl Quinazolines from 2-Aminobenzylamines in Water
作者:Tanmay Chatterjee、Dong In Kim、Eun Jin Cho
DOI:10.1021/acs.joc.8b00327
日期:2018.7.20
transition-metal-free procedure for the synthesis of a highly valuable class of heteroaromatics, quinazolines, was developed by using easily available 2-aminobenzylamines and α,α,α-trihalotoluenes. The transformation proceeded smoothly in the presence of only sodium hydroxide and molecular oxygen in water at 100 °C, furnishing a variety of 2-aryl quinazolines. The crystallization process of the crude
Tri- and dibromination of methyl-, dimethyl-, and trimethylbenzenes with N-bromosuccinimide were accomplished by photothermal reaction with a tungsten lamp in carbon tetrachloride or benzene. (Dibromomethyl)arenes and (tribromomethyl) derivatives were produced depending upon a solvent used and a substituent on the benzene ring. In the bromination of methylbenzenes without a substituent on the ortho-position, (tribromomethyl)benzenes were formed. On the other hand, ortho-substituted methylbenzenes gave (dibromomethyl)benzenes. α,β-Dibromo-1,2-diarylstilbenes were formed via the debrominative carbon–carbon coupling reaction of (tribromomethyl) benzenes upon irradiation with a tungsten lamp.
Bromination of toluene and its meta- and para-substituted derivatives with NBS by irradiation using a tungsten lamp gave benzotribromides and cis- and trans-1,2-dibromo-1,2-diarylethylenes, while ortho-substituted toluenes gave benzal bromides. o-Xylene gave tetra- and pentabromides and m-xylene afforded a mixture of dibromodiarylethylenes.