Direct Conversion of Carboxylic Groups to Furans.

We have developed a novel photoredox deoxygenative reaction to directly transform carboxylic acids to multisubstituted furan compounds. This transformation employs carboxylic acids and vinyl ketones as starting materials and proceeds through a cascade mechanism involving photoredox-catalyzed acyl radical formation and subsequent acid-catalyzed cyclization, synergistically enabling the direct conversion of carboxylic acids to furan heterocycles. The furan derivatives obtained through this carboxylate-based route hold significant application value and provide a convenient strategy for accessing novel heterocyclic frameworks that are often challenging to prepare by using conventional methods. This work opens a new pathway for the efficient construction of valuable furan-based structures from readily available carboxylic acid feedstocks.