1: 80 percent / Na / diethyl ether / 12 h 2: 78 percent / pyridinium chlorochromate / CH2Cl2 / 2 h 3: 54 percent 4: 1) 9-BBN; 2) 6N NaOH, 30percent H2O2 / 1) 2h, THF; 2) 0 deg C; 3) 50 deg C View Scheme