NaBH(HFIP)3 in tetrahydrofuran; hexafluoroisopropyl alcohol T=25°C; 24 h; chemoselective reaction;

1: 80 percent / imidazole / dimethylformamide / 3 h / 0 °C 2: 62 percent / NaBH4 View Scheme

1: 80 percent / imidazole / dimethylformamide / 3 h / 0 °C 2: 62 percent / NaBH4 View Scheme

1.1: 89 percent / PBr3 / CH2Cl2 / 12 h / 0 °C 2.1: 89 percent / toluene / 2 h / 100 °C 3.1: n-BuLi / tetrahydrofuran / -78 °C 3.2: tetrahydrofuran 4.1: 0.24 g / Bu4NF / tetrahydrofuran / 1 h View Scheme

1.1: 89 percent / PBr3 / CH2Cl2 / 12 h / 0 °C 2.1: 89 percent / toluene / 2 h / 100 °C 3.1: n-BuLi / tetrahydrofuran / -78 °C 3.2: tetrahydrofuran 4.1: 0.24 g / Bu4NF / tetrahydrofuran / 1 h View Scheme