sodium hydride in tetrahydrofuran 1.) THF, 0 deg C, 0.5 h, 2.) 20 deg C, 1 h;

1: N-benzenesulfonyl-3-bromopyrrole With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-78°C; Inert atmosphere; 2: anhydrous N,N-diethylformamide in tetrahydrofuran; hexane T=-78 - 0°C; regioselective reaction;

1: N-benzenesulfonyl-2,4-dibromopyrrole With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: formic acid ethyl ester in tetrahydrofuran; hexane T=-78°C; 1 h; Inert atmosphere; regioselective reaction;

1: N-benzenesulfonyl-3-bromopyrrole With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-78°C; Inert atmosphere; 2: anhydrous N,N-diethylformamide in tetrahydrofuran; hexane T=-78°C; regioselective reaction;

1: N-benzenesulfonyl-3-bromopyrrole With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-78°C; Inert atmosphere; 2: N,N-dimethyl-formamide in tetrahydrofuran; hexane T=-78°C; regioselective reaction;

1.1: N-bromosuccinmide / N,N-dimethyl-formamide / 0.5 h / 20 °C 2.1: trifluorormethanesulfonic acid / toluene / 1 h / 0 °C / |Inert atmosphere 2.2: 24 h / 0 - 20 °C / |Inert atmosphere 3.1: n-butyllithium / hexane; tetrahydrofuran / 0.5 h / -78 °C / |Inert atmosphere 3.2: 1 h / -78 °C / |Inert atmosphere View Scheme

1.1: trifluorormethanesulfonic acid / toluene / 1 h / 0 °C / |Inert atmosphere 1.2: 24 h / 0 - 20 °C / |Inert atmosphere 2.1: n-butyllithium / hexane; tetrahydrofuran / 0.5 h / -78 °C / |Inert atmosphere 2.2: 1 h / -78 °C / |Inert atmosphere View Scheme