91. Direct decarboxylative C–N coupling with dioxazolones mediated by a base

Niu, B.-H.; Xia, X.-R.; Ran, L.; Zhang, Y.-X.; Jiang, Y.-Y.;* Jiang, H.;* Cheng, W.-M.* Org. Chem. Front. 2024, 11, 6126–6134. Download Link

The classic Curtius rearrangement provides an efficient method for converting carboxylic acids into amine derivatives but has safety concerns. Herein, we report a general and powerful method for the direct decarboxylative C–N coupling of alkyl and aryl carboxylic acids with dioxazolones in the presence of a base. A diverse array of amides, especially acylated chiral amines, can be synthesized under transition-metal-free conditions at room temperature, offering an alternative to the classic Curtius rearrangement. On the basis of mechanistic investigations, a distinctive mechanism involving multiple nucleophilic addition–eliminations, acyl transfers and a Lossen-type rearrangement is proposed for this unpredicted stereoretentive transformation.