in dimethyl sulfoxide T=135°C; Decarboxylation; 6 h;

1.1: NaH / tetrahydrofuran / 1 h / 0 °C 1.2: 56 percent / tetrahydrofuran / 16.5 h / 0 - 20 °C 2.1: NaH / dimethylformamide / 0.08 h / 0 °C 2.2: dimethylformamide / 2.5 h / 10 °C 3.1: 5 N NaOH / dimethylsulfoxide / 0.08 h / 20 °C 4.1: dimethylsulfoxide / 6 h / 135 °C View Scheme

1.1: NaH / dimethylformamide / 0.08 h / 0 °C 1.2: dimethylformamide / 2.5 h / 10 °C 2.1: 5 N NaOH / dimethylsulfoxide / 0.08 h / 20 °C 3.1: dimethylsulfoxide / 6 h / 135 °C View Scheme

1: 5 N NaOH / dimethylsulfoxide / 0.08 h / 20 °C 2: dimethylsulfoxide / 6 h / 135 °C View Scheme

1: 1.) diisopropylamine, BuLi, 3.) CO2, Br2 2: 2.) aq. KI3 View Scheme

I2 Yield given. Multistep reaction;