1: 76 percent / K2CO3 / acetonitrile / 72 h / 45 °C 2: 1. n-butyllithium / 1. -20 deg C, THF, hexane 2. a. -80 deg C, b. warm up to -10 deg C, 75 min c. 90 min, -10 deg C 3: 68 percent / aq. oxalic acid / tetrahydrofuran / 1 h / Ambient temperature 4: 86 percent / K2CO3 / 1 h / 23 °C 5: 13.5 mg / tetrabutylammonium fluoride / tetrahydrofuran / 25 h / 20 °C 6: aq. NaOH / methanol / 5 h / Ambient temperature View Scheme