描述了通过铜(II)促进或电化学氧化 2-偶氮联芳基来合成苯并[ c ]辛啉鎓盐。通过该策略可以轻松构建多种不同官能化的苯并[ c ]辛啉鎓盐,具有优异的官能团耐受性和高效率。具有电子推拉取代的苯并[ c ]辛啉鎓盐显示出以 571 nm 为中心的有趣荧光。该机制被认为是通过氧化剂驱动的单电子转移和通过亲核加成的分子内环化,然后进行阴离子交换。
Synergistic combination of visible-light photo-catalytic electron and energy transfer facilitating multicomponent synthesis of β-functionalized α,α-diarylethylamines
作者:Yanan Wu、Yipin Zhang、Mingjie Jiang、Xunqing Dong、Hitesh B. Jalani、Guigen Li、Hongjian Lu
DOI:10.1039/c9cc02465d
日期:——
combination of electron and energy transfer processes has been developed. The mild reaction conditions allow the radical–radical cross-coupling phenomenon for the multicomponent synthesis of β-arylsulfonyl(diarylphosphinoyl)-α,α-diarylethyl-amines from readily available arylsulfinic acids (diarylphosphine oxides), 1,1-diarylethylenes and arylazides.
A mild CuBr–NMO oxidative system for the coupling of anilines leading to aromatic azo compounds
作者:Shikha Singh、Parul Chauhan、Makthala Ravi、Isha Taneja、Wahajuddin Wahajuddin、Prem. P. Yadav
DOI:10.1039/c5ra12535a
日期:——
been developed utilizing CuBr with N-methylmorpholine N-oxide (NMO/NMMO) for the oxidative coupling of anilines to access symmetrical and unsymmetrical azocompounds in high yield. The reactivity was found to be governed by electronic and stericfactors of anilines.
UV photolysis of powdered crystals of several aryl azides at cryogenic temperatures afforded azo compounds predominantly. In the cases of p-(N-methylacetamido)phenyl azide and 2-azidobiphenyl, a CH insertion product or a carbazole was formed, competing with azo formation. These products can be considered to be formed through topotactic processes when the crystal structures are taken into account. The arylnitrenes generated in the azide crystals were monitored by ESR spectroscopy; they turned out to have extremely long half life-times, compared with those in the gas phase or in solution. Such high kinetic stabilities are ascribed to the inert environment around the generated nitrenes. The decay process of arylnitrenes in the initial stage obeyed a pseudo-first order kinetics; activation parameters were evaluated by Arrhenius plots. The activation enthalpies and entropies indicate that the diffusional processes of arylnitrenes may be the vital factors determining the kinetic stability and the product distribution in the crystalline environment.
Sodium telluride, prepared by heating tellurium and sodium hydride in a 1:2 molar ratio in dry N,N-dimethylformamide, reduces aromatic nitro compounds to azo compounds and thioketones to hydrocarbons under mild conditions.