1: allyl phosphonic acid diethyl ester With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.25 h; 2: benzaldehyde With N,N,N',N',N'',N''-hexamethylphosphoric triamide in tetrahydrofuran; hexane T=-78 - 20°C; Horner-Wadsworth-Emmons reaction; 14 h; Title compound not separated from byproducts;
