Direct Synthesis of Fluoro Bicyclic Compounds with Fluorine

Elemental fluorine under suitable and simply achieved conditions acts as a strong electrophile able to substitute tertiary, including bridgehead, hydrogens of various bicyclic compounds. The skeleton of the bicyclo molecule was usually unchanged, and the yields, even in the worst cases, represent a great improvement for those extremely few fluoro bicyclic compounds that have previously been prepared. A good correlation between the hybridization of the tertiary C-H bond to its ability to be substituted by fluorine was found. The ¹³C NMR spectra reveal some similarities to other fluoro compounds as far as the carbons α and β to the halogen are involved, but no firm rules could be detected for the γ or the ᵟ carbons.