tetrabutyl ammonium fluoride in tetrahydrofuran T=25°C; 6 h;

ammonia in methanol T=25°C; 6 h;

sodium hydroxide in dimethyl sulfoxide T=25°C; 1 h;

1: 82.5 percent / imidazole / dimethylformamide / 36 h / 25 °C 2: 82.5 percent / N-bromosuccinimide, NaN3 / 1,2-dimethoxy-ethane / 0.5 h / 0 °C 3: 45 percent / tert-BuOK / tetrahydrofuran / 2 h / 5 °C 4: 86 percent / n-Bu4NF / tetrahydrofuran / 6 h / 25 °C View Scheme