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Aromatic acids are converted into aryl bromides simply and efficiently via decarboxylation providing new depth and insight into Hunsdiecker-type reactivity., Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.

Due to their ubiquity in nature and frequent use in organic electronic materials, benzothiophenes are highly sought after. Here we set out an unprecedented procedure for the formation of benzothiophenes via the dual vicinal C–H functionalization of arenes that does not require metal catalysis. This one‐pot annulation proceeds through an interrupted Pummerer reaction/[3,3]‐sigmatropic rearrangement/cyclization sequence to deliver various benzothiophene products. The procedure is particularly effective for the rapid synthesis of benzothiophenes from non‐prefunctionalized polyaromatic hydrocarbons (PAHs).