1: With n-butyllithium in tetrahydrofuran; hexane T=-90°C; 0.5 h; 2: With boric acid trimethyl ester in tetrahydrofuran; hexane T=-100°C; 0.333333 h; 3: With hydrogenchloride in tetrahydrofuran; hexane T=-100 - 20°C;

1: 1-benzofuran-5-carbonitrile With n-butyllithium in tetrahydrofuran; hexanes T=-78°C; 0.5 h; 2: boric acid trimethyl ester in tetrahydrofuran; hexanes 0.333333 h; 3: With hydrogenchloride; water in tetrahydrofuran; hexanes 0.5 h;

1.1: 45 percent / 1-methyl-pyrrolidin-2-one / 24 h / Heating 2.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -90 °C 2.2: trimethyl borate / tetrahydrofuran; hexane / 0.33 h / -100 °C 2.3: 86 percent / 2 M HCl / tetrahydrofuran; hexane / -100 - 20 °C View Scheme

1.1: K2CO3; KI 2.1: polyphosphoric acid / chlorobenzene 3.1: 45 percent / 1-methyl-pyrrolidin-2-one / 24 h / Heating 4.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -90 °C 4.2: trimethyl borate / tetrahydrofuran; hexane / 0.33 h / -100 °C 4.3: 86 percent / 2 M HCl / tetrahydrofuran; hexane / -100 - 20 °C View Scheme

1.1: polyphosphoric acid / chlorobenzene 2.1: 45 percent / 1-methyl-pyrrolidin-2-one / 24 h / Heating 3.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -90 °C 3.2: trimethyl borate / tetrahydrofuran; hexane / 0.33 h / -100 °C 3.3: 86 percent / 2 M HCl / tetrahydrofuran; hexane / -100 - 20 °C View Scheme