1: 91 percent / 1N HCl / methanol / 0 °C 2: hexamethyldisilazane / pyridine 3: trimethylsilyl triflate, Et3N / CH2Cl2 / 24 h / 40 °C 4: 1N HCl / methanol / 0.17 h / 0 °C 5: 92 percent / pyridinium dichromate / dimethylformamide / Ambient temperature View Scheme

Multi-step reaction with 5 steps 1: 100 percent / 2N HCl / methanol2: 77 percent / 1) LDA / tetrahydrofuran / -78 °C / 1) 40 min, 2) 1 h3: 91 percent / LiBH4, methanol / 1,2-dimethoxy-ethane / 2 h / 50 °C4: imidazole / dimethylformamide / 40 °C5: 93 percent / imidazole / dimethylformamide / 40 °C  

With  hydrogenchloride in  methanol T=0°C;