formic acid

1: 87 percent / NaBH3CN / methanol; tetrahydrofuran / 20 h / 0 °C 2: trimethylsilyl triflate / CH2Cl2 / 0.5 h / 0 °C 3: AcOH / methanol 4: NaBH3CN / tetrahydrofuran; methanol / 19.5 h / 0 °C 5: HCl, anisole / H2O; tetrahydrofuran / 17 h / Ambient temperature View Scheme

formic acid

1: 15 percent / NaOEt / ethanol / 12 h / 20 °C 2: ammonium formate / Pd/C / methanol / 2 h / -10 °C 3: 3.3 g / N,N-diisopropylamine / dimethylformamide / 16 h / 20 °C View Scheme