24 h;

Multi-step reaction with 3 steps 1: 48 percent / CrO3; pyridine / CH2Cl2 / 48 h2: 77 percent / L-Selectride / tetrahydrofuran / 4 h / -78 - -20 °C3: 37 percent / pyridine; dimethylaminopyridine / CH2Cl2 / 24 h  

With  sodium hydroxide; sodium amalgam T=20°C; 18 h;