1: 94 percent / tetrabutylammonium hydroxide / methanol / 3 h / Ambient temperature 2: Et3N / 2 h / 6 °C 3: 81 percent / K2CO3, tris(3,6-dioxa-heptyl)amine / toluene / 6 h / Heating 4: 99 percent / aq. NaOH / methanol / 1.25 h / Heating 5: 2 N HCl View Scheme

Multi-step reaction with 3 steps 1: BF3*OEt2 / acetic acid / 18 h / Heating2: p-toluenesulfonic acid / 18 h / Heating3: 97 percent / K2CO3 / dimethylsulfoxide / 18 h / Ambient temperature