1: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature 2: 59 percent / t-BuOK / 2-methyl-propan-2-ol / 2.5 h / 60 °C View Scheme

1: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature 2: 59 percent / t-BuOK / 2-methyl-propan-2-ol / 2.5 h / 60 °C 3: 79 percent / tetrabutyl ammonium fluoride / tetrahydrofuran / 0.33 h / Ambient temperature View Scheme

1H-imidazole in N,N-dimethyl-formamide 3.5 h; Ambient temperature;

With  acetic acid T=65°C; 6 h;   

Multi-step reaction with 3 steps 1: 87 percent / NaBH4 / ethanol / 2 h / Ambient temperature2: 77 percent / pyridine / 24 h / Ambient temperature3: 73 percent / 80percent acetic acid / 6 h / 65 °C