1: 2-(1H-Pyrazole-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane With sodium hydride in N,N-dimethyl-formamide T=20°C; 1 h; 2: ethyl iodide in N,N-dimethyl-formamide T=20°C; 72 h;

(1,1'-bis(diphenylphosphino)ferrocene)palladium(II) dichloride; potassium acetate in 1,4-dioxane T=100°C; 12 h; Inert atmosphereSealed tube;

1: With trifluoroacetic acid in dichloromethane 2 h; 2: With 0.5CO3(2-)*C13H21NPol(1+) in methanol

potassium carbonate in N,N-dimethyl-formamide T=60°C;

4 A molecular sieve in tetrahydrofuran T=20°C; 2 h;

1.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -90 °C 1.2: trimethylborate / tetrahydrofuran; hexane / 0.5 h / -70 °C 1.3: 44 percent / aq. ammonium chloride / tetrahydrofuran; hexane / 1 h / 20 °C 2.1: 78 percent / molecular sieves 4 Angstroem / tetrahydrofuran / 2 h / 20 °C View Scheme