15-crown-5; sodium hydride in N,N-dimethyl-formamide T=-4 - 4°C;

1: 93 percent / aqueous sodium hydroxide / methanol / 6 h / Heating 2: 53 percent / triphenylphosphine; diethyl azodicarboxylate / dioxane / 18 h / 20 °C 3: sodium borohydride / Pd/C / methanol; H2O View Scheme

sodium hydroxide in methanol 6 h; Heating;