sodium tetrahydroborate; potassium dihydrogenphosphate in methanol; water T=22 - 32°C;

1: 90 percent / pyridine / CH2Cl2 / -30 - 20 °C 2: 84 percent / NaBH4, KH2PO4 / methanol; H2O / 22 - 32 °C View Scheme

1: 100 percent / NEt3 / CH2Cl2 / 2 h / 0 °C 2: 1.) NaNO2, Ac2O, 2.) Zn, HOAc / 1.) HOAc, 0 deg C, 2.) 0 deg C, 3 h 3: 84 percent / NaH / dimethylformamide / 0.5 h / 0 °C 4: 1.) H2, 2.) 6N aq. HCl / 1.) Pd(0) / 1.) MeOH, RT, 1 bar, 4 h, 2.) MeOH, 110 deg C, 14 h View Scheme

triethylamine in dichloromethane T=0°C; 2 h;