ferric chloride-DMF-complex in tetrahydrofuran; tetrachloromethane ((3-Furyl)((2-(phenylthio)-5-(trimethylsilyl)-4-pentynyl)oxy)carbene)pentacarbonylchromium was heated at 80°C for 8h. addn of FeCl3-DMF-complex; residue was solved in CCl4 and treated with CF3CO2H; stirring for 30 min; chromy. (silica gel, 3:10 EtOAc/hexane); H-NMR, 13C-NMR, m.p. elem. anal., mass spectrum;

Yield given. Multistep reaction;

1: 93 percent / triethylamine / CH2Cl2 / 0.17 h 2: 89 percent / tri-n-butylamine, 99 percent formic acid / bis(triphenylphosphine)palladium acetate / dimethylformamide / 2.5 h / 70 °C 3: 1.) K2CO3, MCPBA / 1.) CH2Cl2/toluene, -78 deg C, 2.) toluene, reflux, 7 h 4: 50 percent / PDC, 3 Angstroem molecular sieves, anh. acetic acid / CH2Cl2 / 2 h / Ambient temperature View Scheme