Alkyl substituents on the double bond
2,3-Dimethyl-2-butene has four alkyl substituents on the double bond. This alkene is more stable than 2,3-dimethyl-1-butene and 2-ethyl-1-butene, each of which has two substituents on the double bond; these are about uniformly stable. All of these alkenes are more stable than 3,3-dimethyl-1-butene, which has one alkyl substituent on the double bond.