试比较下列烯烃的稳定性请说明原理.
问题描述：
试比较下列烯烃的稳定性
请说明原理.
答
c>b>a
答
烯烃取代基越多越稳定：
b>c>a
Stability:
There are 3 factors that influence alkene stability:
1.Degree of substitution:more highly alkylated alkenes are more stable,so tetra > tri > di > mono-substituted.
烷基取代基越多越稳定：四取代>三取代>二取代>单取代.
2.Stereochemistry:trans > cis due to reduced steric interactions when R groups are on opposite sides of the double bond.
反式>顺式.
3.Conjugated alkenes are more stable than isolated alkenes.
共轭>不共轭.