sulfuric acid; acetic acid in water T=50°C; 1 h;

boron trichloride in dichloromethane T=0°C;

1.1: m-chloroperbenzoic acid / CH2Cl2; H2O / 15 h / 20 °C 1.2: 90 percent / K2CO3 / methanol / 0.5 h / 25 °C 2.1: 99 percent / Et3N / tetrahydrofuran / 2 h / 25 °C 3.1: 94 percent / N-iodosuccinimide; trifluoroacetic acid / acetonitrile / 12 h / 40 °C 4.1: 90 percent / CuI; Et3N / PdCl2(PPh3)2 / acetonitrile / 12 h / 25 °C 5.1: 98 percent / hydrazine monohydrate / tetrahydrofuran / 2 h / 25 °C 6.1: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 7.1: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 8.1: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme

1: 99 percent / Et3N / tetrahydrofuran / 2 h / 25 °C 2: 94 percent / N-iodosuccinimide; trifluoroacetic acid / acetonitrile / 12 h / 40 °C 3: 90 percent / CuI; Et3N / PdCl2(PPh3)2 / acetonitrile / 12 h / 25 °C 4: 98 percent / hydrazine monohydrate / tetrahydrofuran / 2 h / 25 °C 5: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 6: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 7: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme

1: 94 percent / N-iodosuccinimide; trifluoroacetic acid / acetonitrile / 12 h / 40 °C 2: 90 percent / CuI; Et3N / PdCl2(PPh3)2 / acetonitrile / 12 h / 25 °C 3: 98 percent / hydrazine monohydrate / tetrahydrofuran / 2 h / 25 °C 4: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 5: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 6: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme

1.1: t-BuOK / tetrahydrofuran / 0.5 h / 0 °C 1.2: 75 percent / t-BuOK / tetrahydrofuran / 0 - 25 °C 2.1: 90 percent / CuI; Et3N / PdCl2(PPh3)2 / acetonitrile / 12 h / 25 °C 3.1: 98 percent / hydrazine monohydrate / tetrahydrofuran / 2 h / 25 °C 4.1: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 5.1: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 6.1: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme

1.1: 94 percent / K2CO3; n-Bu4NI / acetone / 24 h / Heating 2.1: m-chloroperbenzoic acid / CH2Cl2; H2O / 15 h / 20 °C 2.2: 90 percent / K2CO3 / methanol / 0.5 h / 25 °C 3.1: 99 percent / Et3N / tetrahydrofuran / 2 h / 25 °C 4.1: 94 percent / N-iodosuccinimide; trifluoroacetic acid / acetonitrile / 12 h / 40 °C 5.1: 90 percent / CuI; Et3N / PdCl2(PPh3)2 / acetonitrile / 12 h / 25 °C 6.1: 98 percent / hydrazine monohydrate / tetrahydrofuran / 2 h / 25 °C 7.1: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 8.1: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 9.1: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme

1: 90 percent / CuI; Et3N / PdCl2(PPh3)2 / acetonitrile / 12 h / 25 °C 2: 98 percent / hydrazine monohydrate / tetrahydrofuran / 2 h / 25 °C 3: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 4: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 5: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme

1: 90 percent / CuI; Et3N / PdCl2(PPh3)2 / acetonitrile / 12 h / 25 °C 2: 98 percent / hydrazine monohydrate / tetrahydrofuran / 2 h / 25 °C 3: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 4: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 5: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme

1: 87 percent / thiourea; Cs2CO3; CBr4 / PdI2 / tetrahydrofuran / 2 h / 50 °C 2: 93 percent / H2 / Pd/C / ethyl acetate / 24 h / 25 °C 3: 93 percent / AcOH; H2SO4 / H2O / 1 h / 50 °C View Scheme