| abstract |
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. |