Chemistry Reference
In-Depth Information
In the second phase of this transformation, illustrated below, a six-membered ring
is formed through an intramolecular 1,2-addition. Subsequent protonation of the
alkoxide anion and elimination of water generates the final product.
This sequence of steps is known as the Robinson annulation.
4. Explain the following reactions in mechanistic terms. Show arrow pushing.
As presented in this chapter, olefins can become protonated under acidic con-
ditions, leading to the formation of electrophilic and cationic carbon atoms.
Furthermore, because olefins have nucleophilic character, they can add to sites
of positive charge. The cascading of this mechanism, illustrated below, generates
polycyclic systems through the cation-
p
cyclization.
