1: 96 percent / LiAlH4 / tetrahydrofuran / 1.5 h / - 70 deg C up to r.t. 2: Et3N, SO3*pyridine / dimethylsulfoxide / 1 h / 20 °C 3: 1) potassium tert-butoxide / 1) THF, 10 deg C, 10 min, 2a) -78 up to -50 deg C, 1 h, 2b) -25 deg C, 30 min 4: methanol, HCl, acetyl chloride / 4 h / Heating View Scheme