EDA mediated S–N bond coupling of nitroarenes and sodium sulfinate salts

Abstract

We report the design and application of a sulfinate–nitroarene electron donor–acceptor (EDA) complex and its subsequent use in the first visible light-mediated and catalyst-free synthesis of N-hydroxy-sulfonamides.

A General Platform for Visible Light Sulfonylation Reactions Enabled by Catalytic Triarylamine EDA Complexes

“…Additional electron-withdrawing groups other than fluorine-containing moieties were tested, providing moderate to very good yields with 4-chloro and 4-cyanobenzene ( 3r, 3s ), and even with electron-poor heteroaromatics such as 2-trifluoropyridine-5-sulfonyl chloride ( 3t ). Nitro containing aromatics proved unsuccessful due to their alternative photochemical pathways . Next, we tested the limits of our system by exploring a selection of heteroatom-containing sulfur chlorides (chlorosulfates and sulfamoyl chlorides) as the high redox potentials of these precursors limits their synthetic application to activation by silanes .…”

“…Nitro containing aromatics proved unsuccessful due to their alternative photochemical pathways. 40 Next, we tested the limits of our system by exploring a selection of heteroatom-containing sulfur chlorides (chlorosulfates and sulfamoyl chlorides) as the high redox potentials of these precursors limits their synthetic application to activation by silanes. 41 Gratifyingly, our conditions produced the desired sulfonate ester and vinyl sulfonamides in moderate to good yields (3u−3x), which could not be improved, despite increases in the reaction time or equivalents of sulfamoyl chlorides.…”

The application of nitroarenes in catalyst‐free photo‐driven reactions

“…In 2023, Li and co‐workers [30] presented a visible light mediated, catalyst‐free S−N coupling reaction to synthesize N‐hydroxy sulfonamide derivatives 54 (Scheme 11). The inclusion of electron‐withdrawing groups in the substrates was identified as a crucial factor for the reaction‘s success.…”

Visible light-induced metal-free cascade denitrogenative borylation and iodination of nitroarenes

“…13,14 The active triplet excited state of nitroarenes could be formed through n → π* excitation with the irradiation of light, which has the potential to act as hydrogen atom transfer (HAT) reagents, EDA complex partners, or ligands for LMCT in metal-catalyzed reactions. [15][16][17][18][19][20][21] Although different reagents have been employed to couple with nitroarenes for diverse transformations, the use of B 2 pin 2 or I 2 as borylation and iodination reagents to react with nitroarenes under visible light for accessing arylboronates and iodobenzenes has not been explored thus far.…”