trichlorophosphate in chloroform T=6 - 20°C; 21.5 h;

1: With n-butyllithium; 2-(dimethylamino)-ethanol in hexane T=0°C; 1 h; 2: With 1,2,2-trichloro-1,1,2-trichloro-ethane in tetrahydrofuran; hexane T=-78°C; 1 h; Further stages.;