In addition to multiple bonds

A -Heterocyclic Carbene Complexes in Additions to Multiple Bonds... 

Elemental fluorine is rarely used in addition to multiple bonds. This is due mainly... 

During a microsecond time frame, which is the typical paramagnetic relaxation time of free radicals, polarized free radicals can participate in addition to multiple bonds, to dioxygen, in hydrogen (electron) transfer, in addition to polyradicals, etc. Products of these reactions are polarized in most cases, and they demonstrate TR ESR signals. 

Wagner-Meerwein rearrangements comprise reorganization of the carbon skeleton in eliminations that lead to olefins, in additions to multiple bonds, and in nucleophilic substitutions. Their common characteristic is that after or during formation of an electron deficiency on a carbon atom an alkyl or aryl group moves to that site from a neighboring carbon atom. The electron deficiency can occur as follows ... 

---