Electrolytic partial fluorination of organic compounds. 55. Highly regio- and stereoselective anodic monofluorination of 2,3-dihydrochroman-4-one andchromone derivatives

Anodic monofluorination at the position a to the oxygen atom of the (E)-3-b enzylidene-2,3-dihydrochroman-4-one derivatives was successfully carried ou t to provide the corresponding 2-fluorochromanones selectively. This is the first regioselective electrochemical fluorination of fused-type, oxygen-co ntaining heterocyclic compounds. Anodic fluorination of a chromone derivati ve also gave a similar fluorinated chromanone stereoselectively.