Visible Light-Driven, Gold(I)-Catalyzed Preparation of Symmetrical (Hetero)biaryls by Homocoupling of Arylazo Sulfones

Abstract

The preparation of symmetrical (hetero)biaryls via arylazo sulfones has been successfully carried out upon visible light irradiation in the presence of PPh 3 AuCl as the catalyst. The present protocol led to the efficient synthesis of a wide range of target compounds in an organic-aqueous solvent under photocatalyst-free conditions.

Effect of Arylazo Sulfones on DNA: Binding, Cleavage, Photocleavage, Molecular Docking Studies and Interaction with A375 Melanoma and Non-Cancer Cells

“…For this reason, using a well-established methodology, we have synthesized a set of arylazo sulfones (1-14, 16, Figure 2) with compounds bearing various electron-donating and withdrawing groups Recently, our team has extensively studied a class of colored shelf-stable derivatives containing a dyedauxiliary group, namely arylazo sulfones (Ar-N = N-SO 2 -R'). Such derivatives underwent the N-S bond homolysis upon visible light irradiation (Figure 1B, path a) and the ensuing loss of a molecule of nitrogen facilitates the formation of Ar˙and R'-S˙O 2 reactive radicals that have been exploited in the preparation of, among the others, arylstannanes [64], (hetero)arylphosphonates [65], aryl selenides and tellurides [66], symmetrical (hetero)biaryls [67], arylboronates [68], sulfonyl fluorides [69], stilbenes and vinyl sulfones [70], trifluoromethylthiolates [71], and (E)-vinyl sulfones [72]. Additionally, arylazo sulfones were able to initiate the polymerization of a broad range of electron-poor olefins [73], or to cause covalent functionalization (arylation) of reduced graphene oxide nanosheets [74] and simultaneous photografting of both aryl and methanesulfonyl groups on a gold surface [75].…”

Synthesis of Aryl Thiocyanates and Aryl Selenocyanates via Visible‐Light Activation of Arylazo Sulfones

“…Such moieties impart both color and photoreactivity to the molecules to which are tethered by generating, under light irradiation, different reactive intermediates useful for synthesis. [38] In particular, arylazo sulfones, that are shelf stable derivatives of aryl diazonium salts bearing the N 2 SO 2 CH 3 dyedauxiliary group were found to be precursors of aryl radicals upon visible light irradiation [39] and employed with success in a wide range of protocols for the formation of both CÀ C [40][41][42] and C-heteroatom bonds. [43,44] In particular, these compounds were successfully employed on the preparation of chalcogen-containing arenes, including trifluoromethylthioarenes, [45] aryl sulfones [46] and aryl alkyl thioethers.…”

“…[43,44] In particular, these compounds were successfully employed on the preparation of chalcogen-containing arenes, including trifluoromethylthioarenes, [45] aryl sulfones [46] and aryl alkyl thioethers. [47] More recently, the potentialities of arylazo sulfone chemistry in combination with those of transition metal catalysts [40,48] has been explored. In view of such premises, we were intrigued to evaluate the synthetic potential of arylazo sulfones as precursors of aryl chalcogen cyanates under visible light driven conditions (Scheme 1b).…”

Cationic Gold(II) Complexes: Experimental and Theoretical Study**

“…The only reactivity of prepared gold(II) complexes studied so far was based on electron transfer processes [20] . However, they were suggested as intermediates in several reactions involving radical chemistry [15,30] . The reactions beyond the electron transfer require a labile coordination site at the gold(II) complexes that could coordinate reactive molecules or radicals.…”

“… [20] However, they were suggested as intermediates in several reactions involving radical chemistry. [ 15 , 30 ] The reactions beyond the electron transfer require a labile coordination site at the gold(II) complexes that could coordinate reactive molecules or radicals. Therefore, we aimed at exploring the generation and properties of gold(II) complexes with bidentate and tridentate ligands.…”