Johnson Solid Gold Nanoclusters as Heterogeneous Visible-Light Photocatalysts for Fukuyama Indole Synthesis

Despite notable advancements in noble metal photocatalysis, improving catalyst efficiency and recyclability remains a key challenge that needs to be addressed to facilitate large-scale synthetic applications. Herein, we have successfully synthesized bisphosphine-protected gold nanoclusters with a distinctive Johnson solid kernel, which serve as efficient and recyclable heterogeneous photocatalysts for visible-light-driven three-component radical couplings in Fukuyama indole synthesis. In contrast to conventional gold complexes, the newly developed cluster-based catalysts can be easily photoexcited to their triplet states by visible light, enabling single-electron transfer with <i>O</i>-acyl oximes, a hitherto unexplored class of electrophiles in gold photocatalysis. Our latest discovery suggests that establishing photocatalytic systems based on atomically precise metal nanoclusters with unique structural and electronic properties represents a promising avenue for advancing chemical synthesis in a sustainable and practical manner.