1: 1.) p-toluene-sulfonic acid, 2.) NaI / 1.) THF, RT, 1 h, 2.) RT, 24 h, acetone 2: 39 percent / n-BuLi, diisopropylamine / tetrahydrofuran; hexane / -78 degC, 30 min and RT, 4 h 3: 1.) O2, 2.) p-toluenesulfonic acid / 1.) Sensitox / 1.) CH2Cl2, 30 min, irradiation, 2.) benzene, 24 h, reflux View Scheme

triethyl borane in hexane T=20°C; 0.5 h; Inert atmosphere;

air; triethyl borane; phenyl silane; In(OAc)3 in tetrahydrofuran; hexane T=30°C; 24 h;