Palladium-catalyzed direct ortho C X bond construction via C H activation of azobenzenes: Synthesis of (E)-1,2-b(2,6-dibromo(chloro)-phenyl)diazene

General Principles for the Design of Visible‐Light‐Responsive Photoswitches: Tetra‐ortho‐Chloro‐Azobenzenes

“…Thes ynthesis of tetra-ortho-substituted azobenzenes is known to be challenging due to the highly sterically congested nature of the central N=Nd ouble bond that is surrounded with four large chlorine substituents.T his limits the use of classical methods for azobenzene synthesis,s uch as the Baeyer-Mills reaction, [45] diazonium coupling [27] or oxidative coupling of anilines, [46] and has inspired the development of methods better suited for these targets:l ate-stage CÀH chlorination [38,47,48] and the reaction of diazonium salts with lithiated aromatic compounds,r eported recently by our group. [49] Here,weuse the latter method to prepare aversatile library of tetra-ortho-chloro-azobenzenes ( Figure 2, Table 1), additionally highlighting the robustness of this method.…”

General Principles for the Design of Visible‐Light‐Responsive Photoswitches: Tetra‐ortho‐Chloro‐Azobenzenes

“…The synthesis of tetra‐ ortho ‐substituted azobenzenes is known to be challenging due to the highly sterically congested nature of the central N=N double bond that is surrounded with four large chlorine substituents. This limits the use of classical methods for azobenzene synthesis, such as the Baeyer–Mills reaction, [45] diazonium coupling [27] or oxidative coupling of anilines, [46] and has inspired the development of methods better suited for these targets: late‐stage C−H chlorination [38, 47, 48] and the reaction of diazonium salts with lithiated aromatic compounds, reported recently by our group [49] . Here, we use the latter method to prepare a versatile library of tetra‐ ortho ‐chloro‐azobenzenes (Figure 2, Table 1), additionally highlighting the robustness of this method.…”

Advances in Application of Azobenzene as a Trigger in Biomedicine: Molecular Design and Spontaneous Assembly

“…[ 83 ] In contrast, introduction of EDGs in the position will increase the electron density of the azo group, reducing the effect of the F atom, [ 92 ] though this still provides a method of regulating the absorption spectrum. Xia's group [ 112 ] reported a convenient method for synthesizing ortho ‐tetrachloro or ortho ‐tetrabromo azoarenes. They used 1,3‐dibromo‐5,5dimethylhydantoin (DBDMH) and trichloro isocyanuric acid (TCCA) as halogenation reagents to achieve palladium(0)‐catalyzed direct ortho ‐bromination and chlorination of azobenzenes, respectively.…”