2-trans-6-cis-nonadienal

2-trans-6-cis-Nonadienal, commonly known as violet leaf aldehyde, is an unsaturated aliphatic aldehyde responsible for the intensely green, watery, and slightly fatty odor characteristic of freshly crushed violet leaves and cucumber. It occurs naturally in trace amounts in violet leaf absolute and various plant materials, but is synthesized commercially due to the extremely low natural concentrations. Formulators prize it for its powerful odor impact at very low concentrations (typically 0.001–0.1% in a fragrance blend), making it a highly efficient green top-note modifier in fine fragrances, functional perfumery, and cosmetic products seeking fresh, aquatic, or floral-green accords.