1: 93 percent / potassium carbonate / methanol; H2O / 3 h 2: 90 percent / lithium diisopropylamide, HMPA / tetrahydrofuran / -78 deg C -> room temperature, overnight 3: 1.) DIBAL-H, 2.) 6percent aq. sulfuric acid / 1.) toluene, hexane, 0 deg C, 3 h, 2.) room temperature, 1 h 4: lithium diisopropylamide, anhydrous zinc chloride / tetrahydrofuran; diethyl ether / -10 °C View Scheme

sodium hydroxide in ethanol T=20°C; 2 h;