1: 67 percent / Na2S*9H2O / methanol / 4 h / Ambient temperature 2: 1.) diethyl cyanophosphonate, 2.) triethylamine / 1.) DMF, -20 deg C, 10 min, 2.) a) -20 deg C, 30 min, b) ambient temperature, 4 h View Scheme

pyridine in tetrachloromethane T=0°C;