Aliphatic bisenals (1a-n), ω-hydroxydienals (2a-n), ω-hydroxy-2-alkenals (3a-d), vinylketones (4a, b), an enon-enal (4c) and three geometric isomers of aliphatic bisenones (5a-g) were synthesized in order to study the relationship between the structure and microbicidal activity.