Palladium-Catalysed Intramolecular Direct Arylation of 2-Bromobenzenesulfonic Acid Derivatives

A palladium‐catalysed intramolecular direct arylation of 2‐bromobenzenesulfonic acid derivatives was found to proceed using 1 mol% of palladium acetate as the catalyst. The influence of the substituents on the phenol moiety of 2‐bromobenzenesulfonic acid phenyl esters reveals that electron‐donating substituents favour the reaction while electron‐withdrawing ones are unfavourable. The reactivity of sulfonamides was also studied and, in all cases, a selective activation at sp2 CH vs. sp3 CH was observed. A sulfonamide bearing both phenyl and benzyl substituents on nitrogen gave selectively the six‐membered ring product.