tetrabutyl ammonium fluoride in tetrahydrofuran T=20°C;

ethyl bromide; magnesium in tetrahydrofuran 1.) room temperature, 1 h, 2.) 1 h; reflux, 3 h, 3.) room temperature, 12 h;

1: trimethylsilylacetylene With n-butyllithium in tetrahydrofuran; hexane T=-78 - 0°C; 1.33333 h; 2: 1,ω-diiodohexane With N,N,N',N',N'',N''-hexamethylphosphoric triamide in tetrahydrofuran; hexane T=20°C; 12 h; Further stages.;