1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 2: 59 percent / ammonia / methanol / 16 h / 80 °C 3: 90.9 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 4: 82.4 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 3 h, 2) 1,2-dichlorethane, a) 5 deg C, 10 min, b) room temperature, 35 min 2: 94.74 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 3: 99.5 percent / TBAF / tetrahydrofuran / Ambient temperature 4: 88.73 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 2 h, 2) 1,2-dichloroethane, a) 5 deg C, 10 min, b) room temperature, 10 min 2: 76 percent / 30percent aq. H2O2, pyridine / CH2Cl2 / 0.5 h / Ambient temperature 3: 78 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 2: 90 percent / mercaptoethanol, sodium methoxide / methanol / 4 h / Heating 3: 90 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 4: 79 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 2 h, 2) 1,2-dichlorethane, a) 5 deg C, 10 min, b) room temperature, 10 min 2: 81.1 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 3: 84.8 percent / TBAF / tetrahydrofuran / 3 h / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 2 h, 2) 1,2-dichloroethane, a) 5 deg C, 10 min, b) room temperature, 10 min 2: 89 percent / n-Bu3SnH, Et3B / benzene; hexane / 4 h / Ambient temperature 3: 80 percent / TBAF / tetrahydrofuran / 3 h / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 2: 85.5 percent / methanol; H2O / 18 h / 85 °C 3: 96.5 percent / 30percent aq. H2O2, pyridine / CH2Cl2 / Ambient temperature 4: 90 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 2: 93 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 3: 83 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 2 h, 2) 1,2-dichlorethane, a) 5 deg C, 10 min, b) room temperature, 10 min 2: 71 percent / 30percent aq. H2O2, pyridine / CH2Cl2 / Ambient temperature 3: 90 percent / TBAF / tetrahydrofuran / 3 h / Ambient temperature View Scheme