toluene-4-sulfonic acid in acetone T=20°C; 5 h;

1.1: 2-nitropropane; NaOEt / ethanol / 65 h / 20 °C 2.1: p-TsOH / toluene 3.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: 0.23 g / hexachloroethane / tetrahydrofuran; hexane / 3.5 h / -78 - 20 °C 4.1: 90 percent / toluene-p-sulfonic acid monohydrate / acetone / 5 h / 20 °C View Scheme

1.1: N-bromosuccinimide; benzoyl peroxide / CCl4 / 40 h / 75 °C 2.1: 2-nitropropane; NaOEt / ethanol / 65 h / 20 °C 3.1: p-TsOH / toluene 4.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 4.2: 0.23 g / hexachloroethane / tetrahydrofuran; hexane / 3.5 h / -78 - 20 °C 5.1: 90 percent / toluene-p-sulfonic acid monohydrate / acetone / 5 h / 20 °C View Scheme

1.1: p-TsOH / toluene 2.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 °C 2.2: 0.23 g / hexachloroethane / tetrahydrofuran; hexane / 3.5 h / -78 - 20 °C 3.1: 90 percent / toluene-p-sulfonic acid monohydrate / acetone / 5 h / 20 °C View Scheme

1: NBS, (PhCO)2O2 / CCl4 2: (i) hexamethylenetetramine, CHCl3, (ii) aq. AcOH, aq. HCl View Scheme

1: SO2Cl2 2: NBS, (PhCO)2O2 / CCl4 3: (i) hexamethylenetetramine, CHCl3, (ii) aq. AcOH, aq. HCl View Scheme