1: 73 percent / 80percent acetic acid / 6 h / 65 °C 2: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature 3: 59 percent / t-BuOK / 2-methyl-propan-2-ol / 2.5 h / 60 °C View Scheme

1: 73 percent / 80percent acetic acid / 6 h / 65 °C 2: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature 3: 59 percent / t-BuOK / 2-methyl-propan-2-ol / 2.5 h / 60 °C 4: 79 percent / tetrabutyl ammonium fluoride / tetrahydrofuran / 0.33 h / Ambient temperature View Scheme

1: 73 percent / 80percent acetic acid / 6 h / 65 °C 2: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature View Scheme

Multi-step reaction with 2 steps 1: 87 percent / NaBH4 / ethanol / 2 h / Ambient temperature2: 77 percent / pyridine / 24 h / Ambient temperature  

With  acetic acid T=65°C; 6 h;