n-butyllithium in tetrahydrofuran; hexane T=-78 - 20°C;

1: 1,4-Dihydroxy-2-butyne With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 1 h; 2: cyclohexanecarbaldehyde in tetrahydrofuran; hexane T=-78 - 20°C;

1: 2-(2-propynyloxy)-tetrahydro-2H-pyran With methyl-magnesium chloride in THF-d8 (tetrahydrofuran-d8) T=0°C; Schlenk techniqueInert atmosphere; 2: cyclohexanecarbaldehyde in tetrahydrofuran T=0 - 20°C; Schlenk techniqueInert atmosphere; Further stages;