1: 33 percent / HI / CH2Cl2 / 0.5 h / -30 °C 2: 74 percent / triethylamine / benzene View Scheme

in hexane; benzene under N2; dropwise addn. of PhSPPh2 in benzene to hexane soln. of complex over 30 min with stirring at -50°C, stirred at room temp. overnight; addn. of H2O, ppt. filtered off, washed (H2O, hexane), recrystd. (CH2Cl2);

niobium bromide T=200°C; 24 h;

hydrogen iodide in dichloromethane T=-30°C; 0.5 h;

1: 38 percent / HI / CH2Cl2 / 0.5 h / -30 °C 2: 75 percent / 2 h / 150 °C View Scheme

niobium bromide T=200°C; 24 h;