1: 4-dimethylamino-1-tert-butyldimethylsilyloxynaphthalene With tert.-butyl lithium in cyclohexane; pentane T=20°C; 72 h; 2: N,N-dimethyl-formamide With sulfuric acid; iodine in cyclohexane; pentane T=0 - 20°C; 3: With jones' reagent in acetone T=0°C; Jones' oxidation; 0.5 h; Further stages.;