Regioselective Electrochemical Fluorination of Organoselenium Compounds: Further Investigation and Clarification of Reaction Mechanism

Regioselective anodic fluorination of alkyl aryl selenides having electron-withdrawing groups such as acetyl, ester, amide, and cyano groups at their α-position was achieved. Anodic fluorination of selenides bearing a weak electron-withdrawing amide group in a divided cell generated stable fluoroselenium salts, which were gradually transformed to α-fluoro products. The stable Pummerer type intermediate, fluoroselenium salts [ArSeFCHRCOOEt]+ were confirmed by the reaction with sodium tetraphenylborate to form aryl phenyl selenides. The fluorinated selenides were illustrated to be useful building blocks for the preparation of α-fluoro-α,β-unsaturated esters.