1: phosphonic acid,diphenyl ester With sodium hydride in tetrahydrofuran T=0°C; 0.5 h; 2: chloroacetic acid N-methyl-N-methoxy-amide in tetrahydrofuran T=0 - 20°C;

triethylamine in dichloromethane

1: diethyl (N-methoxy-N-methylcarbamoylmethyl)phosphonate With sodium hydride in tetrahydrofuran T=-78°C; 2: benzaldehyde in tetrahydrofuran T=-78°C; Title compound not separated from byproducts;