Radicalic coupling

The phenoxy radicals are transformed by reactions which are not enzymatically mediated. The radical may shift in the molecule, may react with an other radical (oxidative coupling, radicalic coupling), may interact with double bonds etc. 

Aporphine-type alkaloids. Aporphines, e.g., isoboldine, are built by radicalic coupling (C 2.3.1) from tetrahydroisoquinolines. In dependence on the position of the hydroxy group attacked by phenol oxidases and the locations of the free radicals either alkaloids of the isoboldine type (Fig. 281) or via dienones and their further rearrangement alkaloids of isothebaine structure are formed (Fig. 282). 

---