trifluoroacetic acid in dichloromethane T=0°C; 1.5 h;

iron; acetic acid T=115°C; Reduction; Michael addition; 0.5 h;

1: 92 percent / K2CO3; 18-crown-6 / acetonitrile / 8 h / Heating 2: aq. NaOH / dioxane / 3 h / 20 °C 3: 5.86 g / K2CO3 / dimethylformamide / 0.75 h / 50 °C 4: O3; Me2S; AcOH / methanol / -78 - 20 °C 5: 4.15 g / benzene / 8 h / Heating 6: 98 percent / Fe; HOAc / 0.5 h / 115 °C View Scheme

1: 4.15 g / benzene / 8 h / Heating 2: 98 percent / Fe; HOAc / 0.5 h / 115 °C View Scheme

1: aq. NaOH / dioxane / 3 h / 20 °C 2: 5.86 g / K2CO3 / dimethylformamide / 0.75 h / 50 °C 3: O3; Me2S; AcOH / methanol / -78 - 20 °C 4: 4.15 g / benzene / 8 h / Heating 5: 98 percent / Fe; HOAc / 0.5 h / 115 °C View Scheme

1.1: 83 percent / DMAP / acetonitrile / 48 h / 20 °C 2.1: LiBEt3H / tetrahydrofuran / 0.5 h / -78 °C 2.2: 76 percent / NaH / tetrahydrofuran / 0 - 20 °C 3.1: 99 percent / CF3COOH / CH2Cl2 / 1.5 h / 0 °C View Scheme

1.1: LiBEt3H / tetrahydrofuran / 0.5 h / -78 °C 1.2: 76 percent / NaH / tetrahydrofuran / 0 - 20 °C 2.1: 99 percent / CF3COOH / CH2Cl2 / 1.5 h / 0 °C View Scheme