1: 1a) s-BuLi / 1a) THF, cyclohexane, -40 to -25 deg C, 1b) -> -50 deg C, 10 min 2) THF,-> -10 deg C, 20 min 2: trifluoroacetic acid / CH2Cl2 / 0.08 h / Ambient temperature 3: trifluoroacetic acid / CH2Cl2 / 48 h / Ambient temperature View Scheme

1: 1) s-BuLi / 1) THF, cyclohexane, -40 to -20 deg C, 2) -40 deg C, 1 min 2: 10percent HCl / ethanol / 0.25 h / Heating View Scheme