1: DMAP / acetonitrile / 2 h / Ambient temperature 2: 72 percent / AIBN, Bu3SnH / toluene / 6 h / 80 °C 3: HCOOH / 2 h / 50 °C 4: pyridine / 2 h / Ambient temperature 5: 1.) hexamethyldisilazane, (NH4)2SO4, 2.) trimethylsilyl triflate / 1.) reflux, 1,2-dichloroethane, RT, 1.5 h 6: 72 percent / NaOEt / 24 h / Ambient temperature 7: 77 percent / methanol / 4 h / Heating View Scheme

1: DMAP / acetonitrile / 2 h / Ambient temperature 2: 72 percent / AIBN, Bu3SnH / toluene / 6 h / 80 °C 3: HCOOH / 2 h / 50 °C 4: pyridine / 2 h / Ambient temperature 5: 1.) hexamethyldisilazane, (NH4)2SO4, 2.) trimethylsilyl triflate / 1.) reflux, 1,2-dichloroethane, RT, 1.5 h 6: 72 percent / NaOEt / 24 h / Ambient temperature View Scheme

1: DMAP / acetonitrile / 2 h / Ambient temperature 2: 72 percent / AIBN, Bu3SnH / toluene / 6 h / 80 °C 3: HCOOH / 2 h / 50 °C 4: pyridine / 2 h / Ambient temperature 5: 1.) hexamethyldisilazane, (NH4)2SO4, 2.) trimethylsilyl triflate / 1.) reflux, 1,2-dichloroethane, RT, 1.5 h 6: 72 percent / NaOEt / 24 h / Ambient temperature 7: 77 percent / methanol / 4 h / Heating 8: 78 percent / pyridine / 2 h View Scheme

Multi-step reaction with 3 steps 1: 93 percent / pyridine / 1,2-dichloro-ethane / 0.5 h / -10 °C2: 51 percent / NaN3 / ethanol / 5 h / Heating3: 1.) formic acid, 2.) pyridine / 1.) 50 deg C, 1 h, 2.) room temp. 2 h