1.1: 59 percent / DIBALH / CH2Cl2; hexane / 1.5 h / -40 °C 2.1: 95 percent / NaH; Bu4NI / tetrahydrofuran / 48 h / Heating 3.1: 25 percent / Bu4NHSO4; Oxone; K2CO3 / 4,5-O-Me2C-3-oxo-THP-2-spiro-4'-2',2'-Me2-1',3'-dioxolan / acetonitrile; various solvent(s); H2O / 1.5 h 4.1: 98 percent / NH4OH / tetrahydrofuran / 2 h / 130 °C 5.1: 80 mg / PPh3; DIAD / tetrahydrofuran / 17 h / Heating 6.1: DIAD; TFA / CH2Cl2; H2O / 1.5 h / 20 °C 6.2: 1.7 mg / KOH / CH2Cl2; H2O / 0.5 h / Heating 7.1: 92 percent / Na; NH3 / diethyl ether / 5 h / -78 - 20 °C View Scheme

diisobutylaluminium hydride in dichloromethane T=-40°C;

1: 1.) LiOH; 2.) HCl / acetone; H2O / 1.5 h / Heating 2: 1.) 1,1'-carbonyldiimidazole / CH2Cl2 / 1.) 0 deg C, 45 min; 2.) 0 deg C to RT, 14 h View Scheme