1: With 4,4'-di(tert-butyl)-[1,1-biphenyl]yllithium in tetrahydrofuran T=-100 - -41°C; 2: With 1,2-dibromo-1,1,2,2-tetrafluoroethane in tetrahydrofuran T=-41 - 20°C;

1.1: 84 percent / pyridine / CH2Cl2 / 12 h / 50 °C 2.1: lithium 4,4'-di-tert-butylbiphenylide / tetrahydrofuran / -100 - -41 °C 2.2: 51 percent / BrCF2CF2Br / tetrahydrofuran / -41 - 20 °C View Scheme

1.1: 32 percent / SnCl2; AcOH; aq. HCl / 1 h / 20 °C 2.1: 84 percent / pyridine / CH2Cl2 / 12 h / 50 °C 3.1: lithium 4,4'-di-tert-butylbiphenylide / tetrahydrofuran / -100 - -41 °C 3.2: 51 percent / BrCF2CF2Br / tetrahydrofuran / -41 - 20 °C View Scheme

1.1: 80 percent / NaH / tetrahydrofuran / 36 h / Heating 2.1: 32 percent / SnCl2; AcOH; aq. HCl / 1 h / 20 °C 3.1: 84 percent / pyridine / CH2Cl2 / 12 h / 50 °C 4.1: lithium 4,4'-di-tert-butylbiphenylide / tetrahydrofuran / -100 - -41 °C 4.2: 51 percent / BrCF2CF2Br / tetrahydrofuran / -41 - 20 °C View Scheme