trans-2-Hexenal

Say itTRANZ-TOO-HEK-suh-nal

Sharp, fresh green apple peel and cut leaves, slightly fatty.

What it is: A molecule made in a lab.
Where it comes from: synthetic, natural in leaves and apples
When you smell it: Top notes: the first minutes.
What perfumers do with it: Tiny doses add crisp, unripe-fruit greenness to apple, pear and green accords.
Worth knowing: With leaf alcohol, it belongs to the 'green leaf volatiles' that make freshly mown lawns smell green.
Rules: Limited. Skin sensitizer; IFRA dose limits by product type
Also called: Leaf aldehyde; (E)-2-hexenal

Not on the label of any of the 232 perfumes read so far.

Sources