[realdon]

My textbook says that the 1,4-addition is more stable than the 1,2-addition for conjugated compounds. However, the only reason it gives for this rule is because 1,4-additions have more substituted alkenes than 1,2-additions. This is true for only some molecules. For example, cyclohexadiene has the same number of substitutes for both 1,2-additions and 1,4-additions. Is there another reason for this or does this rule only apply when different number of substitutes occur?

Thanks a lot

[refid]

1,4 addition is the thermodynamic product and is more stable (slower to form)

1,2 addition is the kinetic product and is less stable (faster to form)

I think the 1,4 addition will produce the product that having groups on either side of the double bond.

[Alpha-Omega]

The discussion at the end of these lecture notes may help....example