triethylamine in dichloromethane 0.5 h; Ambient temperature; Yield given;

Multi-step reaction with 3 steps 1: 1) n-BuLi / 1) THF, hexane, -78 deg C, 30 min, 2) THF, -78 deg C, 4 h2: 90 percent / p-toluenesulfonic acid / methanol / 1.5 h / Ambient temperature3: 11 percent / aq. HCl / dioxane / 18 h / Ambient temperature