Rhenium-Catalyzed [4 + 1] Annulation of Azobenzenes and Aldehydes via Isolable Cyclic Rhenium(I) Complexes
作者:Xiaoyu Geng、Congyang Wang
DOI:10.1021/acs.orglett.5b00938
日期:2015.5.15
The first Re-catalyzed [4 + 1] annulation of azobenzenes with aldehydes was developed to furnish 2H-indazoles via isolable and characterized cyclic ReI-complexes. For the first time, the acetate-acceleration effect is showcased in Re-catalyzed C–H activation reactions. Remarkably, mechanistic studies revealed an irreversible aldehyde-insertion step, which is in sharp contrast to those of previous Rh-
A new approach has been established for Rh(iii)-catalyzed direct aza oxidative cyclization of non-prefunctionalized azobenzenes to provide 2-aryl-2H-benzotriazoles in good yields.
Rhenium-catalyzed C–H aminocarbonylation of azobenzenes with isocyanates
作者:Xiaoyu Geng、Congyang Wang
DOI:10.1039/c5ob01121c
日期:——
The first C–H aminocarbonylation of azobenzenes with isocyanates is achieved by using rhenium-catalysis, which provides an atom-economical access to o-azobenzamides.
<i>ortho</i>-Heteroarylation of Azobenzenes by Rh-Catalyzed Cross-Dehydrogenative Coupling: An Approach to Conjugated Biaryls
作者:Hong Deng、Hongji Li、Lei Wang
DOI:10.1021/acs.orglett.6b01277
日期:2016.7.1
A direct cross-dehydrogenative coupling strategy for ortho-C–H activation and functionalization of azobenzenes with heteroarenes in the presence of a Rh catalyst was developed. Excellent regioselectivity was achieved by azo-coordinated Rh to realize oxidative C–H/C–H cross-coupling, providing a series of π-conjugated biaryls in good yields.
A new approach for highly regioselective iodination of azobenzenes with alkyl iodide as the iodinating reagent enabled by Rh-catalyzedoxidativeC–Hactivation has been developed. By changing the oxidant, various mono- and di-iodinated azobenzenes were smoothly obtained in moderate to excellent yields, respectively. The preliminary mechanistic study reveals that the reaction process might undergo electrophilic