NOVEL AND PRACTICAL PREPARATION OF ALPHA-FLUORO-FUNCTIONALIZED ESTERSFROM FLUOROIODOACETATES

The addition reaction of fluoroiodoacetates 2 to various electron-rich alkenes 3 initiated by iron powder in dry THF at 70-80 degrees C gave 1 : 1 adducts 4 in good yields. A variety of functionalities in the a lkenes such as trimethylsilyl, alkoxy, acetoxy, hydroxy and ester coul d be tolerated under the reaction conditions. Reduction of the adducts 4 with Zn-AcOH in ethanol or Zn-NiCl2 . 6H(2)O in moist THF was readi ly accomplished, and the overall procedure was amenable to a convenien t one-flask procedure, Treatment of fluoroiodoacetates 2 with electron -deficient alkenes 7 in the presence of an Fe-CrCl3 . 6H(2)O-bpy bimet al redox system in ethanol at 70-80 degrees C resulted in the formatio n of iodine-free 1 : 1 adducts 8 in moderate to good yields. It is pro posed that the addition reactions of fluoroiodoacetates 2 to electron- rich and electron-deficient alkenes proceeded through a single-electro n-transfer mechanism.