1: With 1-propanephosphonic acid cyclic anhydride; N-ethyl-N,N-diisopropylamine in ethyl acetate T=0°C; 0.166667 h; 2: With sodium tetrahydroborate in water; ethyl acetate T=0°C; 0.583333 h;

sodium tetrahydroborate in ethylene glycol dimethyl ether; water T=-15°C; 0.00833333 h; Yield given;

sodium tetrahydroborate in methanol T=20°C;

1: 1.) NaH / 1.) DMF, -15 deg C, 2 h, 2.) DMF, RT, 5 h 2: 1.) N-hydroxysuccinimide, dicyclohexylcarbodiimide, 2.) NaBH4 / 1.) THF, a) 0 deg C, 30 min, b) RT, 6 h, 2.) THF, EtOH, 0 deg C, 30 min View Scheme

1: 1.) NaH / 1.) DMF, -15 deg C, 2 h, 2.) DMF, RT, 5 h 2: 1.) N-hydroxysuccinimide, dicyclohexylcarbodiimide, 2.) NaBH4 / 1.) THF, a) 0 deg C, 30 min, b) RT, 6 h, 2.) THF, EtOH, 0 deg C, 30 min View Scheme