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

• Published in: Angewandte Chemie International Edition Vol. 54; no. 38; pp. 11200 - 11204
• Main Authors: Le Vaillant, Franck, Courant, Thibaut, Waser, Jerome
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 14-09-2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Acids; Alkynes; amino acids; Biology; Carboxylic acids; Catalysis; hypervalent iodine; Iridium; Light irradiation; Photocatalysis; Photocatalysts; Synthesis; hypervalent iodine; photocatalysis; alkynes; amino acids; carboxylic acids
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201505111

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 α‐amino and α‐oxo acids derived from biomass.
EBX‐cellent: A range of alkynes can be synthesized in good yields by the direct reaction of readily available carboxylic acids with ethynylbenziodoxolone (EBX) reagents in the presence of an iridium photocatalyst (see figure). This decarboxylative alkynylation reaction proceeds at room temperature under visible light irradiation, and could be applied to silyl‐, aryl‐, and alkyl‐substituted alkynes.