1: 84 percent / 2,4,6-trichlorobenzoyl chloride; Et3N; DMAP / tetrahydrofuran; toluene / 12 h / 20 °C 2: 81 percent / DBN / benzene / 8 h / 20 °C 3: 82 percent / 2,4,6-trichlorobenzoyl chloride; Et3N; DMAP / tetrahydrofuran; toluene / 12 h / 20 °C 4: 77 percent / TMSCl; NaI / acetonitrile / 6 h / -20 °C 5: 79 percent / DBN / benzene / 8 h / 20 °C 6: 67 percent / 2,4,6-trichlorobenzoyl chloride; Et3N; DMAP / tetrahydrofuran; toluene / 24 h / 90 °C 7: 90 percent / DDQ / CH2Cl2; H2O / 20 °C View Scheme

1: 80 percent / HCl / dioxane; H2O / 12 h / 20 °C 2: 84 percent / 2,4,6-trichlorobenzoyl chloride; Et3N; DMAP / tetrahydrofuran; toluene / 12 h / 20 °C 3: 81 percent / DBN / benzene / 8 h / 20 °C 4: 82 percent / 2,4,6-trichlorobenzoyl chloride; Et3N; DMAP / tetrahydrofuran; toluene / 12 h / 20 °C 5: 77 percent / TMSCl; NaI / acetonitrile / 6 h / -20 °C 6: 79 percent / DBN / benzene / 8 h / 20 °C 7: 67 percent / 2,4,6-trichlorobenzoyl chloride; Et3N; DMAP / tetrahydrofuran; toluene / 24 h / 90 °C 8: 90 percent / DDQ / CH2Cl2; H2O / 20 °C View Scheme

1.1: 98 percent / imidazole / dimethylformamide / 2.5 h / 0 - 20 °C 2.1: 2M aq. NaOH / methanol / 12 h / 20 °C 3.1: DCC; DMAP / CH2Cl2 / 72 h / 20 °C 4.1: 87 percent / aq. AcOH / tetrahydrofuran / 15 h / 70 - 110 °C 5.1: 75 percent / DCC; (+)-camphorsulfonic acid; DMAP / CH2Cl2 / 48 h / 20 °C 6.1: 79 percent / aq. AcOH / tetrahydrofuran / 48 h / 80 °C 7.1: 79 percent / DCC; DMAP; (+)-comphorsulfonic acid / CH2Cl2 / 48 h / 20 °C 8.1: 96 percent / aq. AcOH / tetrahydrofuran / 3 h / 80 °C 9.1: Zn dust; aq. AcOH-AcONa buffer / tetrahydrofuran / 2.5 h / 20 °C 10.1: 2,4,6-trichlorbenzoyl chloride; 4A mol sieves; Et3N / 3 h / 20 °C 10.2: DMAP / toluene / 24 h / 100 °C 11.1: 75 percent / AlCl3; m-xylene / CH2Cl2 / 2 h / 0 °C View Scheme

1.1: DCC; DMAP / CH2Cl2 / 72 h / 20 °C 2.1: 87 percent / aq. AcOH / tetrahydrofuran / 15 h / 70 - 110 °C 3.1: 75 percent / DCC; (+)-camphorsulfonic acid; DMAP / CH2Cl2 / 48 h / 20 °C 4.1: 79 percent / aq. AcOH / tetrahydrofuran / 48 h / 80 °C 5.1: 79 percent / DCC; DMAP; (+)-comphorsulfonic acid / CH2Cl2 / 48 h / 20 °C 6.1: 96 percent / aq. AcOH / tetrahydrofuran / 3 h / 80 °C 7.1: Zn dust; aq. AcOH-AcONa buffer / tetrahydrofuran / 2.5 h / 20 °C 8.1: 2,4,6-trichlorbenzoyl chloride; 4A mol sieves; Et3N / 3 h / 20 °C 8.2: DMAP / toluene / 24 h / 100 °C 9.1: 75 percent / AlCl3; m-xylene / CH2Cl2 / 2 h / 0 °C View Scheme

1.1: 2M aq. NaOH / methanol / 12 h / 20 °C 2.1: DCC; DMAP / CH2Cl2 / 72 h / 20 °C 3.1: 87 percent / aq. AcOH / tetrahydrofuran / 15 h / 70 - 110 °C 4.1: 75 percent / DCC; (+)-camphorsulfonic acid; DMAP / CH2Cl2 / 48 h / 20 °C 5.1: 79 percent / aq. AcOH / tetrahydrofuran / 48 h / 80 °C 6.1: 79 percent / DCC; DMAP; (+)-comphorsulfonic acid / CH2Cl2 / 48 h / 20 °C 7.1: 96 percent / aq. AcOH / tetrahydrofuran / 3 h / 80 °C 8.1: Zn dust; aq. AcOH-AcONa buffer / tetrahydrofuran / 2.5 h / 20 °C 9.1: 2,4,6-trichlorbenzoyl chloride; 4A mol sieves; Et3N / 3 h / 20 °C 9.2: DMAP / toluene / 24 h / 100 °C 10.1: 75 percent / AlCl3; m-xylene / CH2Cl2 / 2 h / 0 °C View Scheme

1.1: sodium hydroxide / tetrahydrofuran; methanol / 3 h / 20 °C / Inert atmosphere 1.2: 0 °C / Inert atmosphere 2.1: 4-(N,N-dimethlyamino)pyridine; camphor-10-sulfonic acid; dicyclohexyl-carbodiimide / dichloromethane / 3 h / 20 °C / Inert atmosphere 3.1: methanol; pyridinium p-toluenesulfonate / 6 h / 20 °C / Inert atmosphere 4.1: 4-(N,N-dimethlyamino)pyridine; camphor-10-sulfonic acid; dicyclohexyl-carbodiimide / dichloromethane / 12 h / 20 °C / Inert atmosphere 5.1: methanol; pyridinium p-toluenesulfonate / 24 h / 20 °C / Inert atmosphere 6.1: morpholine; tetrakis(triphenylphosphine) palladium(0) / tetrahydrofuran / 12 h / 20 °C / Inert atmosphere 6.2: Inert atmosphere 7.1: 2,4,6-trichlorobenzoyl chloride; triethylamine / toluene / 1 h / 20 °C / Inert atmosphere 7.2: 7 h / 80 °C 8.1: trifluoroacetic acid / dichloromethane / 5 h / 20 °C / Inert atmosphere View Scheme

1.1: di-isopropyl azodicarboxylate; triphenylphosphine / tetrahydrofuran / 0.17 h / 0 °C / Inert atmosphere 1.2: 0 - 20 °C / Inert atmosphere 2.1: potassium carbonate / 2 h / 20 °C / Inert atmosphere 3.1: 4-(N,N-dimethlyamino)pyridine; N-ethyl-N,N-diisopropylamine / dichloromethane / 0.25 h / 0 °C / Inert atmosphere 3.2: 0 - 20 °C / Inert atmosphere 4.1: sodium hydroxide / tetrahydrofuran; methanol / 3 h / 20 °C / Inert atmosphere 4.2: 0 °C / Inert atmosphere 5.1: 4-(N,N-dimethlyamino)pyridine; camphor-10-sulfonic acid; dicyclohexyl-carbodiimide / dichloromethane / 3 h / 20 °C / Inert atmosphere 6.1: methanol; pyridinium p-toluenesulfonate / 6 h / 20 °C / Inert atmosphere 7.1: 4-(N,N-dimethlyamino)pyridine; camphor-10-sulfonic acid; dicyclohexyl-carbodiimide / dichloromethane / 12 h / 20 °C / Inert atmosphere 8.1: methanol; pyridinium p-toluenesulfonate / 24 h / 20 °C / Inert atmosphere 9.1: morpholine; tetrakis(triphenylphosphine) palladium(0) / tetrahydrofuran / 12 h / 20 °C / Inert atmosphere 9.2: Inert atmosphere 10.1: 2,4,6-trichlorobenzoyl chloride; triethylamine / toluene / 1 h / 20 °C / Inert atmosphere 10.2: 7 h / 80 °C 11.1: trifluoroacetic acid / dichloromethane / 5 h / 20 °C / Inert atmosphere View Scheme

1.1: 4-(N,N-dimethlyamino)pyridine; N-ethyl-N,N-diisopropylamine / dichloromethane / 0.25 h / 0 °C / Inert atmosphere 1.2: 0 - 20 °C / Inert atmosphere 2.1: sodium hydroxide / tetrahydrofuran; methanol / 3 h / 20 °C / Inert atmosphere 2.2: 0 °C / Inert atmosphere 3.1: 4-(N,N-dimethlyamino)pyridine; camphor-10-sulfonic acid; dicyclohexyl-carbodiimide / dichloromethane / 3 h / 20 °C / Inert atmosphere 4.1: methanol; pyridinium p-toluenesulfonate / 6 h / 20 °C / Inert atmosphere 5.1: 4-(N,N-dimethlyamino)pyridine; camphor-10-sulfonic acid; dicyclohexyl-carbodiimide / dichloromethane / 12 h / 20 °C / Inert atmosphere 6.1: methanol; pyridinium p-toluenesulfonate / 24 h / 20 °C / Inert atmosphere 7.1: morpholine; tetrakis(triphenylphosphine) palladium(0) / tetrahydrofuran / 12 h / 20 °C / Inert atmosphere 7.2: Inert atmosphere 8.1: 2,4,6-trichlorobenzoyl chloride; triethylamine / toluene / 1 h / 20 °C / Inert atmosphere 8.2: 7 h / 80 °C 9.1: trifluoroacetic acid / dichloromethane / 5 h / 20 °C / Inert atmosphere View Scheme

1: 96 percent / 4-(dimethylamino)pyridine; camphorsulfonic acid; dicyclohexylcarbodiimide / CH2Cl2 / 14 h / 20 °C 2: 19 percent / CH3CO2H / propan-2-ol; H2O 3: triethylamine / toluene / 1 h / 20 °C 4: triethylamine; 4-(dimethylamino)pyridine / toluene / 3.5 h / 80 °C 5: 90 percent / trifluoroacetic acid / CH2Cl2 / 7.5 h / 20 °C View Scheme

1: triethylamine / toluene / 1 h / 20 °C 2: triethylamine; 4-(dimethylamino)pyridine / toluene / 3.5 h / 80 °C 3: 90 percent / trifluoroacetic acid / CH2Cl2 / 7.5 h / 20 °C View Scheme