EP3608302B1 - Process for Preparing a 5-Alken-1-Yne Compound, (6z)-1,1-Dialkoxy-6-Nonen-2-Yne Compound, (2e,6z)-2,6-Nonadienal and (2e)-Cis-6,7-Epoxy-2-Nonenal, and 1,1-Dialkoxy-6-Nonen-2-Yne Compound