Chemistry Reference
In-Depth Information
carbocation, there are no protons adjacent to the carbocation, no direct E1 elimination
products can form. However, if a 1,2-alkyl shift occurs, the resulting tertiary
carbocation can participate in such reactions. Potential E1 elimination products are
illustrated below using arrow pushing.
Like Problems 3(b) and 3(c), this is a solvolysis reaction. However, due to the
increased complexity of the starting compound, the potential product mixture is
more complex. Specifically, if we consider the initial solvolysis step and elimination
of water, we notice that an allyl carbocation is formed that is adjacent to a migratable
hydrogen atom. While this carbocation can undergo an E1 elimination reaction, a
1,2-hydride shift generates a new carbocation that is also capable of E1 forming
E1 elimination products. Furthermore, if the positive charge migrates through the
double bond (see arrow pushing), an allylic carbocation adjacent to a tert-butyl
group results. While this new carbocation bears no adjacent hydrogen atoms, a
1,2-alkyl shift generates a new carbocation that does possess adjacent protons.
This new carbocation can liberate E1 elimination products. All potential E1 elimin-
ation products are illustrated below using arrow pushing.
