diisobutylaluminium hydride in dichloromethane T=-78°C; 1 h; Yield given;

1: oxalyl chloride, DMSO / CH2Cl2 / 0.5 h / -78 °C 2: 1) KHMDS, 18-crown-6 / 1) THF, toluene, -78 deg C, 15 min, 2) THF, -78 deg C, 45 min, then -78 deg C -> 0 deg C, 19 h 3: DIBAH / CH2Cl2 / 1 h / -78 °C View Scheme

1: 1) KHMDS, 18-crown-6 / 1) THF, toluene, -78 deg C, 15 min, 2) THF, -78 deg C, 45 min, then -78 deg C -> 0 deg C, 19 h 2: DIBAH / CH2Cl2 / 1 h / -78 °C View Scheme