1: 85 percent / 1.) n-BuLi; 2.) I2 / tetrahydrofuran; hexane / 1.) -78 deg C, 1 h; 2.) -78 to 25 deg C 2: 1.) disiamylborane; 2.) glacial acetic acid; 3.) 3N NaOH, 30percent H2O2 / 1.) THF; 2.) THF, 50 deg C, 3 h 3: 73 percent / n-BuLi / diethyl ether; pentane / 1.) -78 deg C; 2.) 25 deg C over 1 h View Scheme

bromine; triphenylphosphine in acetonitrile T=0°C;