1: sodium hydrogencarbonate / methanol 2: triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran / 14 h / -23 - 20 °C 3: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 4: hydrogenchloride; water / tetrahydrofuran / 8 h / |Reflux View Scheme

1: sodium hydrogencarbonate / methanol 2: triphenylphosphine; diethylazodicarboxylate / tetrahydrofuran / 14 h / -23 - 20 °C 3: tetrabutyl ammonium fluoride / tetrahydrofuran / 2 h / 20 °C 4: hydrogenchloride; water / tetrahydrofuran / 8 h / |Reflux View Scheme