What does allylic mean?
Allylic is a technical adjective in organic chemistry used to describe anything connected with the allyl group, the three-carbon unit CH₂=CH–CH₂– that features a carbon–carbon double bond next to a saturated carbon. Most often, chemists use the term to refer to the 'allylic position' — the carbon atom immediately adjacent to a double bond — because atoms or groups attached there enjoy unusual reactivity due to resonance stabilization. Reactions described as allylic substitutions, oxidations, or rearrangements are staples of synthetic chemistry, appearing constantly in research papers, textbooks, and patents. The word derives ultimately from 'allium', the botanical genus of garlic, since early chemists first encountered the underlying group in compounds isolated from garlic oil. Though meaningless outside scientific contexts, allylic is indispensable vocabulary for students and practitioners of chemistry, marking one of the most reactive and synthetically useful sites in organic molecules.
adjectiveRelating to or characteristic of the allyl group (CH₂=CH–CH₂–), especially describing the carbon atom adjacent to a carbon–carbon double bond in an organic molecule.
- Of or relating to the allyl group (CH₂=CH–CH₂–) in organic chemistry.
- Describing the carbon atom directly adjacent to a carbon–carbon double bond, and reactions occurring at that position.
"The reaction proceeded by attack at the allylic position, leaving the double bond intact."
"Hydrogen abstraction at the allylic carbon yields a resonance-stabilized radical."
"The drug's synthesis relies on a selective allylic oxidation step."
The word traces back to garlic: chemists named the allyl group after 'Allium sativum' because one of its first known derivatives was isolated from garlic oil.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of allylic
The term derives from 'allyl', the name chemists gave to the group CH₂=CH–CH₂– in the mid-19th century, which itself comes from 'Allium', the Latin genus name for garlic, because the compound allyl sulfide was first obtained from garlic oil. The suffix '-ic' follows the standard pattern for forming adjectives from chemical radicals. Its closest relatives are other allium-derived terms such as 'alliaceous' and 'allicin'.
How allylic is actually used
Strictly a technical term used in organic chemistry; it carries no everyday register and appears almost exclusively in academic, industrial, and patent literature.
Easily confused with allylic
"Allyl" is the noun naming the chemical group CH₂=CH–CH₂– itself, while "allylic" is the adjective describing compounds or positions related to that group.