1: 84 percent / DIBAL / CH2Cl2 / -78 °C 2: 90 percent / pyridine / 4-dimethylaminopyridine / CH2Cl2 3: 1) nBuLi, 2) H2O2 / 1) THF, -78 deg C View Scheme

1: 90 percent / pyridine / 4-dimethylaminopyridine / CH2Cl2 2: 1) nBuLi, 2) H2O2 / 1) THF, -78 deg C View Scheme

n-butyllithium; dihydrogen peroxide 1) THF, -78 deg C; Yield given. Multistep reaction;