Synthetics
4-methyl-2-pentenal smells like a green, fruity, and slightly herbal flavoring ingredient.
Mosciano, Gerard P&F 16, No. 5, 71, (1991): Pungent, etherial, fresh green apple-like, aldehydic, cognac and woody
Luebke, William tgsc, (2009): Ethereal spicy green grassy aldehydic cooked apple cognac woody
Kingchem Laboratories: Strong, green, fruity aldehyde
FCI SAS: Fruity aldehyde, green, strong