Electrolytic Partial Fluorination of Organic Compounds. 22.1 Highly Regioselective Anodic Monofluorination of Oxindole and 3-Oxo-1,2,3,4-tetrahydroisoquinoline Derivatives: Effects of Supporting Fluoride Salts and Anode Materials

Highly regioselective monofluorination of 1-aryl-3-(phenylthio)oxindoles and 2-substituted-3-oxo-4-(phenylthio)-1,2,3,4-tetrahydroisoquinolines can be successfully carried out in the presence of Me 4 NF·4HF or Et 4 NF·3HF as a supporting electrolyte to provide the corresponding 3-fluorinated oxindole and 4-fluorinated isoquinoline derivatives in good yields. Carbon anodes as well as a platinum anode were found to be effective for the fluorination when Me 4 NF·4HF was used as the supporting electrolyte.