1: 53 percent / pyridine / 10 h / 50 °C 2: 95 percent / NaH / Ambient temperature 3: 48 percent / p-toluenesulfonic acid / tetrahydrofuran; methanol / 16 h / Ambient temperature 4: 1.) NEt3 / 1.) benzene, RT, 4 h, 2.) CH3CN, 65 deg C View Scheme

Multi-step reaction with 2 steps 1: 53 percent / pyridine / 10 h / 50 °C2: 95 percent / NaH / Ambient temperature