Asymmetric-waveform alternating current-promoted silver catalysis for C-H phosphorylation

Preventing metal deposition by cathodic reduction is a formidable challenge during transition-metal-catalysed electrosynthesis under direct current (d.c.) electrolysis conditions, especially for noble metal catalysis. To overcome the limitation of reductive metal deposition, we now report an asymmetric-waveform alternating current (a.c.) electrolysis protocol for silver-catalysed C-H phosphorylation, where our a.c.-based approach achieves smooth regeneration of the silver catalyst. A wide variety of alkynes, alkenes and (hetero)arenes are reactive under our a.c. electrolysis conditions, delivering the desired phosphite ester derivatives (88 examples) in good yields, whereas these products are often obtained in poor yields under d.c. electrolysis conditions. Notably, this protocol can be expanded to Pd- and Cu-catalysed C-H functionalization. This electrochemical metal-catalysis strategy is distinct from traditional d.c. electrosynthesis and has great potential to be used in the fine organic chemical industry.