sodium hydrogencarbonate T=20°C;

1: 1.) n-butyllithium, 2.) I2 / 1.) THF, hexane, from -78 deg C to 20 deg C, 1 h, 2.) -78 deg C, 2 h 2: 1.) lithium diisopropylamide / 1.) THF, hexane, -78 deg C, 25 min, 2.) room temp., overnight 3: tert-butyllithium / tetrahydrofuran; pentane / 0.08 h / -100 °C 4: tetrahydrofuran / 6 h / -100 - 20 °C View Scheme

1: 1.) lithium diisopropylamide / 1.) THF, hexane, -78 deg C, 25 min, 2.) room temp., overnight 2: tert-butyllithium / tetrahydrofuran; pentane / 0.08 h / -100 °C 3: tetrahydrofuran / 6 h / -100 - 20 °C View Scheme

1: tert-butyllithium / tetrahydrofuran; pentane / 0.08 h / -100 °C 2: tetrahydrofuran / 6 h / -100 - 20 °C View Scheme

in tetrahydrofuran T=-100 - 20°C; 6 h; Yield given;