Synthesis of perfluoroalkylated bipyridines - New ligands for oxidation reactions under fluorous triphasic conditions

Fluorous soluble bipyridines bearing two perfluoroalkylated side chains in the 6,6'- or 4,4'-positions have been prepared in good yields via etherific ation of 6,6'-bis(chloromethyl)-2,2'-bipyridine or C-alkylation of 6,6'-dim ethyl-2,2'-bipyridine. The new ligands L exhibit amphiphilic behaviour with respect to certain fluorous-organic biphasic systems. Nevertheless, their ruthenium complexes (RuLn)X generated in situ are efficient catalysts for t he epoxidation of trans-stilbene in a fluorous triphasic system CH2Cl2/H2O/ C8F18 in the presence of NaIO4. The fluorous phase, where (RuLn)X is trappe d, can be used up to four times without major loss of catalytic activity. ( C) 1999 Elsevier Science Ltd. All rights reserved.