Formaldehyde → 1,4-Decadiyne
Reaktionsgleichung
[CH2:1]([Mg]Br)[CH3:2].[CH2:5]=[O:6].[CH2:7]1[CH2:11]O[CH2:9][CH2:8]1>>[CH:9]#[C:8][CH2:7][C:11]#[C:11][CH2:7][CH2:8][CH2:9][CH2:1][CH3:2].[CH2:5]([OH:6])[C:9]#[C:8][CH2:7][C:11]#[C:11][CH2:7][CH2:8][CH2:9][CH2:1][CH3:2]Komponenten
5
Versuchsvorschrift
A solution of deca-1,4-diyne in THF was prepared following the method indicated in Example 1 and then an equivalent of ethylmagnesium bromide was added thereto at 0°. The mixture was kept at 60° for 45 min. After having added 1,2 equivalent of paraformaldehyde, the mixture was brought to reflux for 3 h. Once cooled, it was extracted with petroleum ether 80:100° and the organic phases were washed with water, then with an aqueous solution saturated with NaCl, dried and evaporated. The obtained residue was chromatographed on a column filled with silica, using as eluting agent a mixture of 1 to 10% of ethyl acetate in cyclohexane. Undeca-2,5-diyn-1-ol was thus obtained in 40% yield.