1: 91 percent / 1,4-diazabicyclo<2.2.2>octane, n-butyllithium / tetrahydrofuran; hexane / 0 degC for 15 min and room t. for 1.5 h, then 0 degC, 1 h, room t., 1 h 2: 95 percent / p-toluenesulfonic acid / benzene / 7 h / Heating 3: 98 percent / lithium diisopropylamide / tetrahydrofuran / 4 h / -78 °C 4: 10 percent / aluminum chloride / CH2Cl2 / 6 h / -78 °C View Scheme

1: trichloroisocyanuric acid (Chloreal) / CCl4 / 20 h / 5 °C 2: 57 percent / sodium bicarbonate / acetone; H2O / 0.5 h / 25 °C View Scheme

tributylphosphine in dichloromethane

2-chloro-3-methyl-benzothiazolium trifluoromethanesulfonate; triethylamine in acetonitrile

iron (III) acetylacetonate in tetrahydrofuran T=0°C;

iron (III) acetylacetonate in tetrahydrofuran T=0°C;