1: 97 percent / 6 N HCl / dioxane / 1 h / Heating 2: 99 percent / potassium tert-butoxide / 2-methyl-propan-2-ol / 0.08 h / Heating 3: 73 percent / CH2Cl2; H2O / 1 h 4: 40 percent / 1.) n-butyllithium, formaldehyde / hexane; tetrahydrofuran / 1.) -25 - -28 deg C, 10 min; 2.) warmed up to 18 deg C for 1 h 5: 93 percent / KOH / methanol / 0.08 h / Heating 6: 90 percent / zinc / acetic anhydride / 0.5 h / 60 °C 7: 30 percent / ceric ammonium nitrate (CAN), pyridine-2,6-dicarboxylic acid N-oxide / acetonitrile; H2O / 1 h / Ambient temperature View Scheme

1: 65 percent / zinc / 0.5 h / 60 °C 2: 74 percent / conc. H2SO4 / methanol / 4 h / Heating View Scheme