substitutedalkene

A substituted alkene is an organic compound characterized by the presence of a carbon-carbon double bond, where at least one of the carbon atoms involved in the double bond is attached to a substituent group other than a hydrogen atom. Alkenes, in general, have the formula CnH2n and contain a carbon-carbon double bond as their functional group. The term "substituted" indicates that hydrogen atoms on the vinylic carbons (the carbons participating in the double bond) have been replaced by other atoms or groups.

The number and nature of these substituents significantly influence the chemical and physical properties of the alkene. The degree of substitution can range from monosubstituted (one substituent, three hydrogens) to disubstituted (two substituents, two hydrogens), trisubstituted (three substituents, one hydrogen), and tetrasubstituted (four substituents, no hydrogens). The substituents can be alkyl groups, aryl groups, halogens, or other functional groups.

Substituted alkenes exhibit geometric isomerism, specifically cis-trans isomerism, when each carbon of the double bond is attached to two different groups. In a cis isomer, identical or similar groups are on the same side of the double bond. In a trans isomer, they are on opposite sides. This stereoisomerism arises from the restricted rotation around the carbon-carbon double bond.

The reactivity of substituted alkenes is primarily associated with the pi bond, which is electron-rich and susceptible to electrophilic attack. The presence of substituents can affect the electron density of the pi system, thereby influencing the regioselectivity and stereochemistry of addition reactions. Electron-donating substituents generally increase the electron density of the double bond, making it more reactive towards electrophiles.