Photocatalytic aerobic α-oxygenation of amides to imides using a highly durable decatungstate tetraphenylphosphonium salt.

Decatungstate is a potent photocatalyst for hydrogen atom transfer (HAT) but faces degradation issues when using a typical tetra- n -butylammonium salt. Herein, we employed tetraphenylphosphonium as a countercation to yield a highly durable and efficient HAT photocatalyst, enabling α-oxygenation of amides to their corresponding imides using O 2 as an oxidant.