Room-Temperature Decarboxylative Alkynylation of Carboxylic Acids Using Photoredox Catalysis and EBX Reagents

Alkynes are used as building blocks in synthetic and medicinal chemistry, chemical biology, and materials science. Therefore, efficient methods for their synthesis are the subject of intensive research. Herein, we report the direct synthesis of alkynes from readily available carboxylic acids at room temperature under visible-light irradiation. The combination of an iridium photocatalyst with ethynylbenziodoxolone (EBX) reagents allowed the decarboxylative alkynylation of carboxylic acids in good yields under mild conditions. The method could be applied to silyl-, aryl-, and alkyl- substituted alkynes. It was particularly successful in the case of alpha-amino and alpha-oxo acids derived from biomass.