1: 3,5-bis-(tert-butyl-dimethyl-silanyloxy)-2-fluorobenzene With sec.-butyllithium in tetrahydrofuran; hexane T=-70°C; 1 h; 2: N,N-dimethyl-formamide in tetrahydrofuran; hexane T=20°C; 1.5 h; Further stages.;

1.1: sec-BuLi / tetrahydrofuran; hexane / 0.5 h / -65 °C 1.2: trimethyl borate / tetrahydrofuran; hexane / 1 h / -65 °C 1.3: 73 percent / aq. H2O2; acetic acid / 0.5 h / 0 °C 2.1: 99 percent / imidazole / dimethylformamide / 1 h / 0 °C 3.1: sec-BuLi / tetrahydrofuran; hexane / 1 h / -70 °C 3.2: 92 percent / tetrahydrofuran; hexane / 1.5 h / 20 °C View Scheme

1.1: 91 percent / imidazole / dimethylformamide / 1 h / 0 °C 2.1: sec-BuLi / tetrahydrofuran; hexane / 0.5 h / -65 °C 2.2: trimethyl borate / tetrahydrofuran; hexane / 1 h / -65 °C 2.3: 73 percent / aq. H2O2; acetic acid / 0.5 h / 0 °C 3.1: 99 percent / imidazole / dimethylformamide / 1 h / 0 °C 4.1: sec-BuLi / tetrahydrofuran; hexane / 1 h / -70 °C 4.2: 92 percent / tetrahydrofuran; hexane / 1.5 h / 20 °C View Scheme

1.1: 91 percent / imidazole / dimethylformamide / 1 h / 0 °C 2.1: sec-BuLi / tetrahydrofuran; hexane / 0.5 h / -65 °C 2.2: trimethyl borate / tetrahydrofuran; hexane / 1 h / -65 °C 2.3: 73 percent / aq. H2O2; acetic acid / 0.5 h / 0 °C 3.1: 99 percent / imidazole / dimethylformamide / 1 h / 0 °C 4.1: sec-BuLi / tetrahydrofuran; hexane / 1 h / -70 °C 4.2: 92 percent / tetrahydrofuran; hexane / 1.5 h / 20 °C View Scheme

potassium fluoride in N,N-dimethyl-formamide T=20°C; 2 h;

potassium fluoride; hydrogen bromide in N,N-dimethyl-formamide T=25°C; 1 h;