1: With sec.-butyllithium in tetrahydrofuran; cyclohexane T=-78°C; 0.5 h; 2: With iodine in tetrahydrofuran; cyclohexane T=-78°C; 0.333333 h; 3: With tetrabutyl ammonium fluoride in tetrahydrofuran T=20°C; 0.166667 h;

tetrabutyl ammonium fluoride in tetrahydrofuran T=0°C; 0.5 h;

1.1: sodium hydride / tetrahydrofuran; mineral oil / 0.33 h / 0 °C 1.2: 0 °C 2.1: n-butyllithium / tetrahydrofuran / 1.5 h / -78 °C 2.2: 1 h / -78 - 0 °C 3.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 0.5 h / 0 °C View Scheme

1.1: 3-chloro-benzenecarboperoxoic acid / ethyl acetate / 1 h / 0 °C 2.1: methanesulfonyl chloride / N,N-dimethyl-formamide / 2 h / 52 - 72 °C 3.1: sodium hydride / tetrahydrofuran; mineral oil / 0.33 h / 0 °C 3.2: 0 °C 4.1: n-butyllithium / tetrahydrofuran / 1.5 h / -78 °C 4.2: 1 h / -78 - 0 °C 5.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 0.5 h / 0 °C View Scheme

1.1: methanesulfonyl chloride / N,N-dimethyl-formamide / 2 h / 52 - 72 °C 2.1: sodium hydride / tetrahydrofuran; mineral oil / 0.33 h / 0 °C 2.2: 0 °C 3.1: n-butyllithium / tetrahydrofuran / 1.5 h / -78 °C 3.2: 1 h / -78 - 0 °C 4.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 0.5 h / 0 °C View Scheme

1.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 0.25 h / 0 °C 1.2: 2 h / 20 °C 2.1: copper(l) iodide / N,N-dimethyl-formamide / 2.5 h / 100 °C 3.1: lithium hydroxide hydrate / water; tetrahydrofuran / 64 h / 20 °C View Scheme

1.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 0.25 h / 0 °C 1.2: 2 h / 20 °C 2.1: copper(l) iodide / N,N-dimethyl-formamide / 2.5 h / 100 °C View Scheme

1: 4-chloro-5-iodo-1H-pyrrolo[2,3-b]pyridine With sodium hydride in N,N-dimethyl-formamide; mineral oil T=0°C; 0.333333 h; 2: benzenesulfonyl chloride in N,N-dimethyl-formamide; mineral oil T=20°C; 2 h;