What is "allyl group"

n. the univalent unsaturated organic radical C3H5; derived from propylene [syn: allyl, allyl radical]

An allyl group is a substituent with the structural formula HC=CH-CHR, where R is the rest of the molecule. It consists of a methylene bridge (-CH-) attached to a vinyl group (-CH=CH). The name is derived from the Latin word for garlic, Allium sativum. In 1844, Theodor Wertheim isolated an allyl derivative from garlic oil and named it "Schwefelallyl". The term allyl applies to many compounds related to HC=CH-CH, some of which are of practical or of everyday importance for example allyl chloride.