1.1: potassium tert-butylate / tetrahydrofuran / 0.5 h / 0 - 5 °C / |Inert atmosphere 1.2: 2 h / 0 - 5 °C 2.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / acetone / 19 - 25 °C / |Inert atmosphere 2.2: 18 h / 20 - 25 °C 3.1: sulfur trioxide pyridine complex; N-ethyl-N,N-diisopropylamine / dichloromethane; dimethyl sulfoxide / 2 h / 6 - 12 °C / |Inert atmosphere 4.1: hydrogenchloride / acetonitrile; water / 4 h / 13 - 20 °C 5.1: carbon / ethyl acetate / 2 h / 20 °C 5.2: 1.5 h / 17 - 25 °C / 2250.23 Torr View Scheme