An efficient and environmentally benign synthesis of phenanthridine by electrochemically oxidative cyclocoupling of biaryl vinyl azide with sodium azide and benzenesulfonyl hydrazide, respectively, is reported. The reaction is carried out in undivided cell at room temperature, without additional metal‐catalysis or exogenous oxidant.
Ruthenium‐catalyzedcycloisomerization of 2‐ethynylbiaryls was investigated to identify an optimal ruthenium catalyst system. A combination of [η6‐(p‐cymene)RuCl2(PR3)] and two equivalents of AgPF6 effectively converted 2‐ethynylbiphenyls into phenanthrenes in chlorobenzene at 120 °C over 20 h. Moreover, 2‐ethynylheterobiaryls were found to be favorable substrates for this ruthenium catalysis, thus
Ruthenium(0)-Catalyzed Cross-Coupling of Anilines with Organoboranes by Selective Carbon–Nitrogen Cleavage
作者:Qun Zhao、Jin Zhang、Michal Szostak
DOI:10.1021/acscatal.9b02440
日期:2019.9.6
activation of neutral carbon–nitrogen bonds is of great synthetic importance, because amines are among the most prevalent motifs across organic and bioactive molecules. Herein, we report the Ru(0)-catalyzed selective cleavage of neutral C(aryl)–N bonds in generic aniline derivatives enabled by a combination of Ru3(CO)12 and an imino auxiliary. These mild conditions provide a direct route to high-value
Poly(ethylene glycol) Supported Liquid Phase Synthesis of Biaryls
作者:Carsten G. Blettner、Wilfried A. König、Wolfgang Stenzel、Theo Schotten
DOI:10.1055/s-1998-1630
日期:1998.3
The liquid phase synthesis of biaryls via Suzuki cross-coupling reaction on poly(ethylene glycol) supports (PEGs) is described. The reaction is exemplified by parallel coupling of polymer bound aryl halides with boronic acids. Four different PEGs were employed as soluble polymer supports for parallel synthesis. The generated libraries include both sterically hindered aryl halides (2b, 2d) and boronic acids. The reactions were run in the homogeneous phase and the synthetic sequences performed in parallel fashion. Quantitative conversion in the Suzuki coupling was verified by 1H-NMR analysis (3a-r). The polymer bound products were isolated in good to excellent (52% to 98%) yields by either simple precipitation of the soluble support or column filtration.
versatile tool for the construction of (hetero)biaryl scaffolds. However, the cross-electrophile coupling using abundant (hetero)arylhalides and pseudohalides is still in its infancy. In particular, a robust and general method for the cross-electrophile coupling would allow unparalleled entry into the vast collection of commercially available, structurally diverse (hetero)arylhalides and pseudohalides