Addition of Molecular Fluorine to C=C Bonds (Especially the Ones in Enone Functions)

Abstract

Some recent topics concerning the addition of molecular fluorine to C=C bonds are discussed together with the mechanistic clarification of the syn-addition and the formation of the rearrangement products. The entire scheme for the addition reaction is the formation of a perpendicular π-complex at the initial stage, which leads to a tight ion pair as the transition state. The tight ion pair then either collapses directly to the syn-addition product, or affords indirectly the carbocation rearrangement product. It is postulated that the direct precursor of the rearrangement products is not a free carbocation but a loose ion pair which is formed from the tight ion pair.