iodine; nitric acid in chloroform 1.) reflux, 4 h, 2.) 5 deg C, 16 h;

Multi-step reaction with 2 steps 1: DBU, 4A sieves / dimethylformamide; benzene / a.) -15 deg C, 1 h, b.) RT, 18 h2: 5percent H2SO4 / 3 h / Heating  

Multi-step reaction with 4 steps 1: 91 percent / tetrabutylammonium fluoride / tetrahydrofuran / 0.5 h2: 1.) Dowex 2(OH-) resin, 2.) 1N HCl / 1.) acetone, water, RT, 24 h3: DBU, 4A sieves / dimethylformamide; benzene / a.) -15 deg C, 1 h, b.) RT, 18 h4: 5percent H2SO4 / 3 h / Heating