1: AcOH, conc. H2SO4 / CH2Cl2 / 16 h / 4 °C 2: 68.5 percent / hexamethyldisilazane, chlorotrimethylsilane, trifluoromethanesulfonic acid / acetonitrile / 12 h / Heating 3: 63 percent / 1,8-diazabicyclo<5.4.0>undec-7-ene (DBU) / toluene / 1.5 h / 90 °C 4: (dimethylamino)pyridine / acetonitrile 5: 85 percent / tributyltin hydride, AIBN / toluene / 120 °C 6: 1.) LiN3, benzoic acid, 2.) 0.1 M NaOCH3 / 1.) DMF, 120 deg C, 12 h, 2.) MeOH View Scheme