sodium tetrahydroborate in methanol T=0°C; 1 h; Title compound not separated from byproducts.;

1.1: 75 percent / (i-Pr)2NEt / CH2Cl2 / 60 h / 20 °C 2.1: 74 percent / NaBH4 / methanol / 0.33 h / -15 °C 3.1: HCO2H; DEAD; PPh3 / tetrahydrofuran / 1.5 h / 20 °C 3.2: 72 percent / Et3N / methanol / 1 h / 20 °C 4.1: 70 percent / CF3CO2H / CH2Cl2 / 2 h / 20 °C View Scheme