CH 11-4: Epoxide Synthesis and Reactions
•Ring with three atoms (C, C, O)
•Very reactive due to ring strain
•Formed during the metabolism
of some toxic compounds.
•Epoxide Synthesis: Intramolecular SN1 or SN2:
Reactions of Epoxides
Nucleophilic substitution resulting in epoxide ring opening:
(1) If acid-mediated (or catalyzed), the nucleophile adds
to the most substituted carbon by anti addition.
(2) If the nucleophile is a strong base (base catalyzed)
all aspects of the reaction resemble SN2 (anti addition).
(3) All epoxide reactions are stereospecific (anti addition).
•General Reaction:
Acid-Mediated Epoxide Ring Opening Mechanism. Write a complete mechanism
for the balanced equation below. Your mechanism must consist of a series of
numbered, balanced equations for each chemical step, and curved arrows to show the
movement of electron pairs. Note the regiochemistry and stereochemistry.
Base Catalyzed Epoxide Ring Opening Mechanism. Write a complete mechanism
for the balanced equation below. Your mechanism must consist of a series of
numbered, balanced equations for each chemical step, and curved arrows to show the
movement of electron pairs. Note the regiochemistry and stereochemistry.