Visible Light-Driven Benzaldoxime Synthesis by Glutathione-Modified CdS Quantum Dots

Inspired by the secondary coordination sphere of nitrite reductase, we report herein the first photocatalytic benzaldoxime synthesis from NO_x ^- (x = 2, 3) and benzyl alcohol. Different from introducing co-catalysts, the integration of glutathione (GSH) relay with CdS quantum dots (QDs) can effectively mediate hole transfer and facilitate selective benzyl alcohol oxidation to benzaldehyde. At the same time, GSH assists continuous proton transfer to promote selective NO_x ^- reduction and form NH₂OH in situ. As a result, the synergic C-N coupling delivers a series of benzyl oximes from NO_x ^- and benzyl alcohols with excellent yield and selectivity. Benzaldoxime synthesis proceeds at a rate of 18.7 mmol g_cat ^-1 h^-1 and TON of 52,875, accomplishing 90.6% benzyl alcohol conversion and 72.3% benzaldoxime yield, which is comparable to the best records for electrocatalytic benzaldoxime synthesis. The excellent long-term recyclability and scaled reaction to produce 0.58 g benzaldoxime with a yield of 41% demonstrate efficient, atom-economic, and step-economic photocatalytic oxime synthesis via selective C-N coupling from abundant resources.