Graphitic Carbon Nitride Polymer as a Recyclable Photoredox Catalyst for Decarboxylative Alkynylation of Carboxylic Acids

Visible-light-induced heterogeneous photocatalysis for decarboxylative alkynylation has been performed. The using of cheap, metal-free and recyclable graphitic carbon nitride (g-C3N4) as the photoredox catalyst in the process enables the facile transformation of a variety of carboxylic acids into structurally diverse alkyne-containing molecular architectures under mild and environmentally-benign conditions. Notably, the heterogeneous nature of the reaction system allows for the recovery and reuse of the catalyst in multiple runs without loss of reactivity. The photocatalytic reactions could also be performed in a continuous flow fashion and scaled up to gram-scale. Furthermore, the preparative power of this strategy is further highlighted by its application in the 1, 2-amido alkynylation of unactivated alkenes.