PREPARATION OF PERFLUOROORGANOSELENIDES FROM PERFLUOROALKENES AND SELENIUM OR DISELENIUM DICHLORIDE

Hexafluoropropene reacts with selenium in dimethylformamide in the presence of CsF at 45-55-degrees-C to form tetrakis(trifluoromethyl)-1,3-diselenetane in 50% yield. With SbF5 the diselenetane forms a dark blue selenium-centered radical-cation. Under mild conditions Se2Cl2 reacts with CF2 = CF2 or CF3CF = CF2 in HOSO2F to yield [FSO2OCF2CFX]2Se2 as a major and FSO2OCF2CFXSeCl (X = F, CF3) as a minor product. In the presence of CsF at 8-10-degrees-C, [FSO2OCF2CF(CF3)]2Se2 reacts with methanol to give [CH3OC(O2)CF(CF3)]2Se2.