An efficient method is disclosed for the preparation of an ω-substituted (E)-2-alken-1-al, e.g., 12-chloro-(E)-2-dodecen-1-al in three steps of reactions. The starting compound is an ω-substituted 1-alkynyl magnesium halide which is reacted with trimethyl or triethyl orthoformate to give an ω-substituted 1,1-dialkoxy-2-alkyne followed by a partial hydrogenation of the triple bond and then hydrolysis or, alternatively, followed by the hydrolysis reaction and then partial hydrogenation of the triple bond.  
                            本发明公开了一种通过三步反应制备ω-取代的(E)-2-烯-1-醛,例如 12-
氯-(E)-
2-十二烯-1-醛的有效方法。起始化合物为ω-取代的 1-炔基卤化
镁,与
原甲酸三甲酯或
原甲酸三乙酯反应,得到ω-取代的 1,1-二烷氧基-2-炔,然后进行三键的部分氢化反应,再进行
水解,或者先进行
水解反应,再进行三键的部分氢化反应。