Allyylinen

Allyylinen refers to a chemical functional group containing a vinyl group directly attached to a methylene group. Its structure can be represented as CH2=CH-CH2-. This arrangement means that the carbon atom directly bonded to the double bond is saturated, distinguishing it from a simple vinyl group. The term "allyl" itself is derived from the Latin word for garlic, allicin, as allylic compounds are found in many alliums.

Allylic compounds are known for their unique reactivity. The allylic carbon atom, due to its proximity to the pi system of the double bond, is susceptible to various chemical transformations. This includes allylic substitution reactions, where a substituent on the allylic carbon can be replaced. Furthermore, the double bond itself can undergo addition reactions. The delocalization of electrons across the allyl system can also lead to resonance stabilization of intermediates.

Examples of common allylic compounds include allyl alcohol (CH2=CH-CH2OH) and allyl chloride (CH2=CH-CH2Cl). These compounds are important intermediates in organic synthesis, finding applications in the production of polymers, pharmaceuticals, and fragrances. The presence of the allylic group imparts specific chemical properties that are exploited in these industrial processes.